AMT top arms - strength

[jiminwatford]

its been posted on another mini forum that the AMT top arms have been known to snap and brake under heavy braking and cornering.

has anyone heard anything on this?

James

[Richspec]

Yes.

PM sent.

[mattcave]

So what's the story then folks? Let's get the facts out in the open, don't keep it a secret...

[Andy@AMT]

In the 8 years of making this frame we have never had any one ring up and say i have broke the top arm. and we have sold over 100. will some one show me one?

[mininut]

So what's the story then folks? Let's get the facts out in the open, don't keep it a secret...

There is nothing to "get out in the open"... they don't snap.

[Andy@AMT]

Do you think we would be still doing the same top arm setup if they kept breaking after all this time. I was in a car not so long ago with one of our frames in and the guy mis-judged the bend and we ended up hitting the barrier at 45-50 mph, the only damage apart from the bodywork was that it broke the top rose joint on the front arm, The only problem we ever had was with a race frame which was being used on the road, which it was never designed for. but the problem was rectified but we also had several other race frames being used for what they were designed for and we never had this problem,

[ChadH]

James,

What forum was it? I'd be interested to read what's been said. It's very easy for rumours to start on this forum, so I think it's only fair to AMT that all of the facts are posted so that any accusations can be answered properly.

[trickey]

Would it be this one?
http://p211.ezboard.com/fminiclassicgeneralqueries.showMessage?topicID=194 08.topic

[MattG]

as i can see this becoming a touchy area , i dont want one line posts saying 'My top arm broke !' , or 'We have never had any broken' etc.. if you have facts / names /dates examples then please say so..

thanks

Matt

[mattcave]

So what's the story then folks? Let's get the facts out in the open, don't keep it a secret...

There is nothing to "get out in the open"... they don't snap.

Didn't mean to imply there WAS anything to get out in the open. What I meant was "let's hear the facts, not the rumour". I'm reasonably confident that if there was (or previously had been) a problem with them then someone on here would know about it. And the thread quoted above is pure rumour so I doubt there *IS* any fact to back it up.

[jiminwatford]

of course matt,

it was on this thread http://p211.ezboard.com/fminiclassicgeneralqueries.showMessage?topicID=194 08.topic

i was enquiring about using metro hubs and asked if instead of lengthening the bottom arms to counter the postive camber i could adjust the top arms in.

someone asked and i put a picture of my frame to demonstrate.

a member replied sayng re the toparms, "under heavy braking and cornering, they have been known to bend and even fail (read snap)

no doubt ATM will spin it that they've been tried and tested blah blah blah, but that's the word when you talk to anyone in the mini 16v rally community (say, allspeed engineering)"

he did not back that up with any substantiating cases or evidence.

i replied i had not heard of any cases in three years of owning an AMT frame.

my post here was to clarify and /or discuss people's opinion/experiences of the arms.

James

[Richspec]

Do you think we would be still doing the same top arm setup if they kept breaking after all this time. I was in a car not so long ago with one of our frames in and the guy mis-judged the bend and we ended up hitting the barrier at 45-50 mph, the only damage apart from the bodywork was that it broke the top rose joint on the front arm, The only problem we ever had was with a race frame which was being used on the road, which it was never designed for. but the problem was rectified but we also had several other race frames being used for what they were designed for and we never had this problem,

So what you are saying is that the race frame isn't strong enough to use on the road but is expected to be ok for use on track :?:
That can't be right :?
Surely track use puts more strain on components than road use.
As I said in my pm to james, my road frame is ok apart fom a bent rosejoint, and i've had mine on the road longer than most.

Rich

[darrell cripps]

I think dave coxon told me that he has been told that the top arms on the AMT frame are s**t :shock: i dont think much of the bottom coilover braket in the pick does it just bolt to the ball joint :?:

[Richspec]

I think dave coxon told me that he has been told that the top arms on the AMT frame are s**t :shock: i dont think much of the bottom coilover braket in the pick does it just bolt to the ball joint :?:

Yes it does just bolt to the balljoint, the race frame top arm is very different to that.

Rich

[mininut]

So what you are saying is that the race frame isn't strong enough to use on the road but is expected to be ok for use on track :?:
That can't be right :?
Surely track use puts more strain on components than road use.

Rich, can you please explain to me how many "Race Tracks" you've seen or been on that have pot holes? other than the illegal ones of course :roll:

And secondly, the simple fact that the quote came from a competitor that if forever commenting on AMT products is ridicules.

And finally, I don't believe that many (if any) AMT framed minis have been rallied, this is simply because they are not designed to do so. The race frame is made for track cars, i.e. no bumps. I'm sure if you ask AMT what the difference is that you will get a more meaningful answer.

Oh and lets not forget my mate told me that his mates other mate, has got a mate that snapped an "Allspeed" frame :roll: I think you understand what I'm saying.

M.

[Richspec]

So what you are saying is that the race frame isn't strong enough to use on the road but is expected to be ok for use on track :?:
That can't be right :?
Surely track use puts more strain on components than road use.

Rich, can you please explain to me how many "Race Tracks" you've seen or been on that have pot holes? other than the illegal ones of course :roll:

And secondly, the simple fact that the quote came from a competitor that if forever commenting on AMT products is ridicules.

And finally, I don't believe that many (if any) AMT framed minis have been rallied, this is simply because they are not designed to do so. The race frame is made for track cars, i.e. no bumps. I'm sure if you ask AMT what the difference is that you will get a more meaningful answer.

Oh and lets not forget my mate told me that his mates other mate, has got a mate that snapped an "Allspeed" frame :roll: I think you understand what I'm saying.

M.

Elvington (my most visited circuit) is not as smooth as say Castle combe, neither was Binbrook :shock: It can't be right that the race frame cannot handle potholes, which are the most severe thing on the road, what about going over the kerbs at the circuit or an 'unplanned excursion' into the kitty litter or across the grass?
I'm getting the impression that the top race arm (not the road one) may be a tad suspect as I'm led to believe :roll:
Its hopefully :!: not going to be an issue, as i might be getting replacement top arms made.

The quote on miniclassic you mean?

finally yes i know what your saying, as Matt said its not the place to spread unsupported rumours :)

PS it better had be strong as my new evolution of the mini will be road legal although 90% track use :D

Rich

[ChadH]

what about going over the kerbs at the circuit or an 'unplanned excursion' into the kitty litter or across the grass?


Only bad racers do that!

:twisted:

[Richspec]

:lol:
Even that german has to find the limits somehow :wink:

Going off topic but if theres any bit i would beef up on the AMT frames its the plate that the tie bar mounts through, mine is bent, i suspect its flexing under pressure, possibly giving rise to the problems i had with the tracking wandering, just my feelings of course. All i intend to do is weld another flat piece on possibly with a small 90 deg lip to stop it flexing.

Rich

[DaveCoxon]

And finally, I don't believe that many (if any) AMT framed minis have been rallied, this is simply because they are not designed to do so.


You're just talking about the Race frame, or the road frame aswell?
We're getting the indication that a frame designed for rallying is the strongest, one designed for typical road use is the intermediate, and then race-only use is the weaker of the three...
So, is an AMT frame used on the road insufficiently strong- as it was only proven for race use? Or are we just talking about the race frame? :?



Finally, If something like a top arm is bent, is it defined as 'broken' or not? It might not have structurally failed, but it has indeed failed from a material /strength/overload aspect...

[mininut]

IIRC

There are two, one for road, and one for track. The road frame deals with pot holes and the like. The race frame is made only for race tracks (Not Rallying, as track and rally stages are two different things)!!

You wouldn't drive a formula ford on the road would you? I don't think that suspension is designed to travel as much as a road car and would break too.

Come on guys, use your heads!! it doesn't take a lot to see that track cars have very little suspension travel. Put one on the road and suspension WILL fail (it's not what it's designed for)

If you want more details then ask AMT.

M.

[Andy@AMT]

Just let me clear something up. The race frame is not designed for the road, simply because you will never get the suspension to work properly i.e. the car has to be so low for the top suspension arm to work with the shock absorber that you would probably rip the exhaust off. We initially designed it for hill climbing and sprint use hence there are'nt any speed humps at these circuits. After all what would be the point of making two frames for the same purpose. The issue with the top arms on the race frame is that the coil-over is positioned to the side and not over the ball joint as on the road one so this creates a different load on the rear arm and this was an issue with Graham from Manchester, his arms had indeed bent at the rear but we have never this issue with anybody elsees race frame but Graham had used his on the road and the others hadnt but when Graham sent his arms back for us to view, we noticed that he had been running his rose joints right at the end of the rod which may have contributed to the higher bending load, When we made the new ones for him we noticed that he wanted them making a lot longer than the ones we supplied which tells me that for him to get the suspension to work on the road he had been running the top arms so far out to get the suspension to work properly that this may have been contributing to the bending of the rear arm and after sending the new arms out which were a lot longer we had a report that he was bending the rose joint so he was still running the suspension wrong as usually you have to saw a bit off the rear arm depending on what hubs you are using. PS enough said my fingers have gone numb. PS I try to help everybody out when they purchase my products.

[FatKev]

I'm probably not going to help matters any, but in defence of Andy -

Okay, so there might be an issue with the arms on the race frame, under certain circumstances....

Why is everyone worried??!

Even mass manufacturers make parts for cars that fail under certain circumstances - ie when used for applications they werent intended for. You know big car companies, that SHOULD have more money to throw at research and development.

I think the bottom line here is - things break on cars :D

I mean any Mini with a big\powerful engine in it will be driven hard most of the time. What happens when you push anything to the limit, too much of the time. Bad stuff! Yeah, thats my technical term...

Take any production car and hammer it around all the time. Stuff will break. By breaking I mean fudging up in general, not just snapping!

Just my 2 pence worth (not really even worth that I suppose, as I have no engineering background whatsoever, however I think I've got some common sense and a fair bit of reasoning\understanding)

Andy nevermind these people - at least AMT has a better record than the likes of Zcars and their bike engined, chain snapping, looney tins. We all know they don't work half the time....

Kevin

[mininut]

Out of the 100's of AMT frames made and sold across the world, has anyone in this community that WE know had a problem with their road AMT frame?? No... I didn't think so. :roll:

People are always too eager to slate a good product, especially competitors in the hope that they can take some business.

M.

[FatKev]

Only problem is if I was going to go the Vauxhall route, I would have wanted the AMT race frame. :shock:

However I don't like the idea of riipping my exhaust apart cos it's too low. Nor do I like the idea of having to trailer my Mini to oocasional track days :!:

Oh well, back to the "piddly" front mounted, FWD, R1 engined plan then...

I hate when this happens on this forum. The rumours or the exagerated truth spreads about certain occurances to do with frames\kits. We should all be ashamed of ourselves :oops:

Kevin

[ChadH]

It sounds like you will mainly be using it on the road, so why don't you just get their road frame? The biggest difference is the suspension set up, and whatever frame you get, you will not be configuring the suspension for race only if you are going to use it on the road.

[mininut]

It sounds like you will mainly be using it on the road, so why don't you just get their road frame? The biggest difference is the suspension set up, and whatever frame you get, you will not be configuring the suspension for race only if you are going to use it on the road.

For a change, I have to agree chadH :D :D

[ChadH]

:shock: :shock: :shock:

You feeling alright, Maz?!?

:twisted:

[mininut]

:P :lol: :lol: :lol:

[FatKev]

Dunno...

You do have a point Chad.

It's a tough choice here... I've sort of gone off the VTEC just due to the sheer cost of the engines and the cost of squeezing more hp's outta those crazy engines. Also the complicated ecu malarky - unless you could get a megasquirt to run it all, or cant use carbs, I'm not intersted! :D

Also, it looks like Richspec had a hard time cramming his XE into that clubman fronted Mini. Reason for the race frame was I wanted a low Mini, but I never actually knew the race frame would make it that low!

As far as I can tell the R1 engine transplant might just be that bit easier. Just the initial costs of a whole engine and the special gearbox to worry about.... hey if I get bored of that I can always move onto a "real" engine cant I? Not much a student with a mortgage can do (I live in Scotland, houses are cheap).

Kevin

[mick]

if Andy has sold at least a hundred frames thats a grand each mmmm ,,,,fu me Andy got any jobs going ?

[mattcave]

Out of the 100's of AMT frames made and sold across the world, has anyone in this community that WE know had a problem with their road AMT frame?? No... I didn't think so. :roll:

People are always too eager to slate a good product, especially competitors in the hope that they can take some business.

M.

Couldn't agree more. I think we've done a pretty good job of getting to the raw facts on this one which is what this community is all about really. Sharing facts, and dispelling myths.

ONE purchaser has had problems with ONE frame when used in somewhat non-standard circumstances. And AMT are up-front about it and have apparently been helpful in trying to fix the problem for that one guy. The fact that Andy has been responsive to the problem rather than saying "you must have mis-used it, it's not my problem" says a lot about his general attitude to his customers.

[mininut]

if Andy has sold at least a hundred frames that’s a grand each mmmm ,,,,fu me Andy got any jobs going ?

I believe Jeff Watson is the man making the money, his frames are £1500+ a pop and he'll build a car for close to 10k. Surprised he doesn't walk round with gold medallions and biatchs.

One thing that Andy does is take pride in his work, unlike a lot of people out there that'll sell you any old rusty sh1t that's just been chopped up and welded together.

M.

[PaulC]

People are always too eager to slate a good product

M.

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:




Pot.......Kettle........Black

[mininut]

People are always too eager to slate a good product

M.

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

Pot.......Kettle........Black

what are you saying then? :roll:

[DaveCoxon]

In the 8 years of making this frame we have never had any one ring up and say i have broke the top arm. and we have sold over 100. will some one show me one?

Graham from Manchester, his arms had indeed bent at the rear but we have never this issue with anybody elsees race frame

:?


The second time his arms bent (or rather the rose joint as you point out :wink: ) it had been trailed to Avon Park after the new arms were fitted. Three runs up the strip, with the heavy braking at the end (in order to get down the first return lane) and his joints were banana shaped. The new arms you made were an increased diameter aswell I recall - not just longer. Basic sense suggests this moved the 'failure' point to the next weakest component - ie the rod end. He now runs the highest quality aurora rod end, and the problem has not re-surfaced.

As you say though, he had clearly not set the frame up properly, as he never needed to mod the arm; so this could have had an effect.


*edited as i had worded something that could have been mis-interpreted very badly* :oops:

[ChadH]

Either way, one failure in over 100. That's less than one percent, and from what I've read, it looks like excellent customer service/after sales support was given too.

I think it's time this post was put to bed!

[mininut]

I think it's time this post was put to bed!
ZZZZZZZzzzzzzzzzzzzz......

There is obviously a lot of rumour going on here and I want to get the facts out as I know them. The bent top arm that everyone is talking about was on my car. It did not break, it bent safely, just putting the tracking and camber out. This happened at Avon Park in 2002. The car has an AMT race frame installed with coil over shocks.

I purchased the AMT race on the understanding that is was not tested for road use. I do use it on the road but in fact I've probably put 1000 miles on it in the last 3 years.

There is mention that the arms were set-up much longer than they were designed for. This is not true. In 2002 the suspension was setup as per AMT specification. After the bent arm incident I added 10.25inch brakes and shortened the King Pin offset to reduce the torque steer. To do this I used a top arm set-up 10mm longer than the AMT (standard) spec. I will go into more detail in a minute but I made these modifications after the bent arm happened.

I am a qualified mechanical engineer in the Automotive industry. I have access to FEA and also metallurgy measuring tools so I used them to understand why it bent and redesign the top arm. This is going to be boring sh1t for most of you but here are my findings:

There is a lot of stress on the arm because of the bottom location for the coil over. This puts a constant stress on the part that becomes greater under braking, cornering, pot holes and rumble strips etc. Now Andy told me that he had one failure on a hill climb car during development so a stronger steel was used for the 1/2inch thick rod and the problem was solved. I did a hardness check where the part was welded (the same place it bent) and the hardness, because of the heat, was down - probably similar to the original low grade steel. Although the strength has gone the advantage is it will bend instead of break.

I then built an FEA model of the suspension of the standard race frame suspension and applied standard Rover suspension loads to the model. These are the worst case design loads used for production cars. The stress was too high, but that's fine. It's not designed for the road and these are worst case scenarios.

I have limited knowledge of racing loads but I also began to look at the braking loads with slick tyres fitted. Nearly all the car weight can be on the front wheels. Braking alone with the grippy slicks takes the suspension to the limit of their safety margin so hard braking and hitting the rumble strip made me feel uncomfortable about driving the car. Is the FEA accurate? It's the best thing I had to work with, plus a bent arm sat on my bench.

I can't say by fact that the arm bent on the drag strip but I checked the car over before trailering it down to Avon Park that day and did not notice the bent arm, but it could have been. I believe that the arm bent at the end of the 1/4mile braking at 100mph. I do tend to brake hard at the end of the quarter. There are even pot holes coming round the return bend.

I want to get something else straight also. I contact Andy@AMT after the incident and after lengthy discussion he agreed to help solve the problem with me. He did not have to do so because I had used the frame on the road, so thanks to Andy for fabricating the stronger parts to my design. Yes they are longer to take my set-up for reduced torque steer and larger brakes. I also made sure that the location of the shock mount was cantilevered as little as possible and I used different spacers to do this.

I had a bent rose joint on the top arm in 2003. You can put this down to the longer arms for argument. I purchased some quality joints for that location and have not had a problem since.

If you have a road frame I think the suspension shock mount is different so I don't think there should be any problem with them. As Andy says it's the offset of the shocker mount that causes the problem on the race frame. If you plan to use it on the road buy a road frame. When all said and done I am happy with the workmanship of the AMT frame. The only weak point in design is the top arm ON THE RACE FRAME which is now sorted for me.

[mininut]

Something I found that RichSpec left of the old forum, just thought folk might find it interesting to see...
http://www.16vminiclub.com/gallery/albums/userpics/amt%20praise.jpg

M.

[FatKev]

C'mon!

As the guy, who's car has been the topic of this thread, has said - it BENT safely!!!!!!!!!

How many of you VTEC boys with the al'mighty Watsons (scrapy Metro jobby with a fair amount of work done to it) subframes have had stuff fail?

I recall certain brackets snapping quite often.... not just bending... snapping, sheering, breaking!

I also like to re-itterate my previosu point - hammer these cars about and thrash em about all the time, stuff will break. No matter how well engineered something is, something is bound to break.... we all know this. Who cares a computer program said "this wont break..." it will at some point for some reason.

Also curious how often Rob Hall (Geoff Watson for that matter) has had failures during his tarmac rally events. Also wander the length of intervals between general strip down and rebuilds (of frame and so on, not just engine). If he can run the same car without taking it apart between events, I'll be gobsmacked and bow down to him :D

Just my general rant for today.

Now, as someone previously said, lets put this thread to rest.... getting fed up of some of the "jokes" getting flung about. Not so funny if the jokes were about your worksmanship\livelihood, now would it. :roll:

a rather disgruntled Kevin

[FatKev]

Do the whole quote and reply thing all you want. I'm just pointing out that no matter what frame you look at, they all have good and bad points, despite what certain people preach on here.

Erm isn't thos thread about the top arm? I dunno about you, but its not exactly the subframe as such, is it? Mind you guess it depends what you think the frame is. I'm talking about subframe kits as a whole.

Also I'm not going to re-read you last post. Just think if it was someone, even just in a funny way, was "joking" about your livlihood.

How can you do tarmac rallying and not have bits break? I don't mean in each event! Also don't tell me Geoff or Rob dont have to replace\repair various bits after enough wear and tear - all things engineered can and will break :(

I'm not backing AMT for any reason at all - I just think some of you guys are too eager (especially Mininut at times) to go nah nah :P my\his subframe is better cos this broke on subframe so and so. Instead of being arses to one another, lets try and better the 16v community.

Note - this whole post (rant) isnt aimed at DarrenW. Also like to appologize for my harsh and inconsiderate tone in recent posts. Was just very annoyed. Sorry!

Kevin

[mininut]

Someone, please just lock the post now!! Or is there a specific pound of flesh that DW is after? :roll:

M.

[mini-GSI]

too much hear'say and conjucture is what was clouding the topic, the facts that are important have been stated and I think everyone has said their peice. if anyone has a problem (specific) maybe its worth posting it seperately or pm's. i think this thread should just be left 'as is'.....

my 2pence worth :oops:

[mininut]

if theres any bit i would beef up on the AMT frames its the plate that the tie bar mounts through, mine is bent, i suspect its flexing under pressure,

The reason I put the post from the old forum back in 2001 was to demonstrate that Rich’s frame was at one point setup correctly and he did reap the benefits of that then.

Consequently he’s done some tinkering with it and possibly introduced more stress to components with incorrect alignment.

Was talking with the other cumbrian AMT customer…Anyway he was telling me he'd had problems with the tracking wandering on his mini. He had taken it to some garage to find out what was going on. They said the frame had a weak point :roll: where the bottom arm etc mounts. His solution to this alleged problem has been to fit a bar right across the bottom of the frame as extra bracing….. I know I've had this problem before, but now my suspension's all over the shop, doesn't even measure the same side to side anymore :( so I can't say for definate mines not knackered somewhere.

So, we are let to believe that the guy in the garage that recommended the extra bracing was a structural engineer!!! :roll:

On the rally car we inserted an upright to sandwich the bottom rose joint, other than that no other alts, it does run a sump guard which strengthens it up a bit.

Rallying as said before is not what the frame was designed for.


DW, All the points you have raised HAVE been addressed in previous posts. So please, can we just leave it now. I certainly won't be replying to any further posts.

M.

[Richspec]

Hi guys, been away all week so a quick catchup.

The other cumbrian AMT owner, he just added that brace cos a garage said the frame was moving, no proof before or after as to what was happening so its a total non event story wise, sorry!

I'll stand by that old post that maz found, it was a crackin day :D
however nothing has been altered apart from spring rates, the tracking was found to be altering all the time in later yrs, it was frustrating i could never get the handling to stay how i wanted, however the rear anti-roll bar was possibly the biggest plus for track use, can't comment on a diff as its still on the kitchen table waiting to go in :roll:

Big thanks to Andy for coming on and explaining what was what and to Graham for putting his side forward too, I'll have another read through when not soo knackered and see if there's anything i missed.

Rich :D