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Any one had a Foot Peg failure? Thruxton

8K views 36 replies 20 participants last post by  norton74 
#1 ·
This possibly applies to Bonnevilles and Scramblers too....

Has anyone experienced a foot peg breaking while riding - i.e. snapped of while standing on them going over a level crossing, stomping on them to get some lean going etc. - NOT breaking due to a drop of fall?

The reason I ask is this: I have just bought a new RH peg as the original had snapped off when the bike toppled over while the previous owner was parking it. These pegs do not look strong at all - they are cast aluminum, and would have expected at least forged and even then, something a little beefier. Now, I have no problem if the peg is designed to break when the bike falls over to prevent further damage to mounting brackets, etc., but I don't think this is the case - it's just a cheaply made part (oh, but it's expensive to buy). My concern is that it up to the job and I just want to have confidence that they are. If no one has had a failure, then all should be well.

For what it's worth, rather than use a rear peg, I adapted a pair of rear pegs from a Yamaha Vigaro which I used while waiting for the replacement Triumph peg. They actually looked pretty good and are definitely stronger than the Triumph pegs - no means of spring loading them though.
 
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#3 ·
Do a search...there are plenty examples of the stock pegs breaking off both while riding and from falling over. Being that you have a Thruxton you should be able to find a set of older Yamaha pegs to replace the stock pegs. The Bonneville/Scram guys only have Oberon or LSL for a replacement peg that bolts on without mods afaik.
 
#4 ·
Compared to some sport-bikes I think the Bonnie pegs & mounts are pretty stout. Have you seen some of the tiny little aneimic pegs on crotch rockets. I have pencil holders that look beefier. Yes most "Cruisers" have big meaty pegs, but weight is not a factor, and have you seen the size of the guys (and gals) that ride those things.:D
It's been a few years since I have heard of a peg failure while standing on it. I stand on mine all the time up to 50mph or so just to clear the "junk" or to avoid a R/R track cramming the seat up my "arse" as the Brits would say.
Now that I have heard it again I will start thinking about it more before I start playing Bud Ekins.
 
#5 ·
The problem is, in my opinion, that the stock pegs are cast, not forged or machined from solid (i.e. "billet"). While casting is a much cheaper manufacturing process and one that can produce complex shapes, the resulting part is weaker and more brittle - not good attributes for a foot peg.

I noticed on the interchangeable parts sticky that there are some Yamaha options and I'll take a look at them. At the end of the day though, as well as being safe, I want it to look right on the bike. If I do find an alternative, I'll let everyone know.
 
#8 ·
Broken peg

Oh yes, riding along minding my own business went over a speed bump and the peg went clattering down the road, leg was flung back etc. Lucky to stay on. Still love the Bonnie though. I do think the mounting bolts are a tad feeble.
 
#9 ·
Suffered a right footage snapping off when riding at about 65mph a couple of days ago. Here's the offending foot peg, with the bolt sheared straight off (I should have cleaned it for the photo but understand it was a mess after bouncing down a wet road and then spending 3 days in a wet bag until I got home). The bike has never seen dropped, the peg has never been removed and put back on again (so not overtightened by accident) and the bike has done less than 15k miles. Basically, the item was factory fitted. I serviced the bike only a couple of days before and I know for sure that the peg wasn't loose, nor did I feel that it was loose at any time whilst riding before it sheared off.

I was lucky to have stayed on the bike, if it had been a fast left hand corner with oncoming traffic in the other lane, the chances are I'd have been seriously injured or killed.

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#11 ·
Hmmm, weird. I have been standing on mine (2010) to stretch my legs for 5 years now without issue... You did say the bike went down on the peg so I would think for sure that weakened it....

Now my buddy's Bonne had one snap off just as we were departing our last stop to head home but he has that single bolt attachment setup! :(
 
#13 · (Edited)
seen it happen today with my own eyes.

out riding with a pal on his black Bonnie and without warning the right hand peg snaps off. lucky he didn't loose control. the results could have been fatal

it would appear the peg bolt was previously cracked after dropping the bike at low speed some months back and today it decided to let go. examining the broken part on the side of the road you could clearly see it partly fractured half way through, then a clean break the rest of the way

anyone who has laid their bike down on the peg, do yourself a big favour and replace the bolt!
preferably up a size from 8mm to 3/8", that being about 9.5mm in diameter. an 8mm bolt has a cross section of about 50 square mm whereas 3/8" has 70 square mm, a big difference in strength. and use either a grade 8 or DIN 12.9
 
#16 ·
The fact that it DOESN'T happen more often indicates it is likely an assembly/maintenance issue, not a design flaw. The picture looks like it cracked initially, possibly due to vibration under load, then corroded until final catastrophic failure.
 
#18 ·
If it were a bad design then every foot peg could be predictably made to fracture at a load that is in the expected envelope of load cases that the foot peg was design to.

Note that the picture of this particular foot peg shows beach marks (lines with rust) indicating fatigue followed by the final fracture when the cross section of the bolt was only about half that of an undamaged bolt.
 
#22 ·
You may be correct Forcetto. On the other hand, there are plenty of other Bonneville riders who aren't forum members that are probably experiencing the same rate of failure. It's hard to say how many are actually getting to the Triumph corporate office. It would be simple enough to forward a link to this thread to them. If they were concerned about the safety of riders they wouldn't necessarily require a formal complaint to follow up on something that appeared to be suspicious.

Toyota and Ford certainly know the cost of ignoring early anecdotal reports of problems.
 
#23 · (Edited)
I would find it hard to believe that there are not any dealers , triumph mechanics etc on this forum .surely they have read about this problem as well as the mysterious stall folks encountered with the efi bikes .one would think triumph must have many reports of these issues ,but they must be keeping their head buried in the sand . Sadly maybe it will take someone getting killed and a huge ass lawsuit for them to finally haul their heads out of their arses .
 
#25 ·
I would find it hard to believe that there are not any dealers , triumph mechanics etc on this forum .surely they have read about this problem as well as the mysterious stall folks encountered with the efi bikes .one would think triumph must have many reports of these issues ,but they must be keeping their head buried in the sand . Sadly maybe it will take someone getting killed and a huge ass lawsuit for them to finally haul their heads out of their arses .
FWIW I sent a link to this thread along with a brief description of the issue to Triumph Motorcycles North America. The person I talked to was not aware of this issue but said he would pass it on to his supervisor.

tma.aftersales@triumphmotorcycles.com
 
#24 ·
When i first learned of this problem i checked the mounts and sure enough they were loose . i replaced the 8mm bolt with a 3/8'' grade 8 and drilled and taped for a 6mm allen bolt between the alinment dimple and top corner of the bracket. there are plenty of fixes on this forum and all probable better than the factory set up. When someone gets hurt and the law suit starts Triumph will have experts blaming it on poor maintenance and explaining how this design can't fail if properly maintained. I decided not to wait, i haven't worried about this for over a year now.
 
#29 ·
When someone gets hurt and the law suit starts Triumph will have experts blaming it on poor maintenance and explaining how this design can't fail if properly maintained. I decided not to wait, i haven't worried about this for over a year now.
I think if it were going to happen, we'd have heard about it by now. They've been using the same design for more than 15 years. I do not think the problem is nearly as common as some think, nor of the cause they believe.
 
#28 ·
NTSB concluded that the gusset plates which connected the
steel beams of the bridge were roughly half the thickness
than they should have been and contributed to the failure of the bridge. NTSB investigators found 16 fractured gusset plates from the bridge’s center span. Their investigation found no evidence that cracking, corrosion or other wear 'played any role in the collapse of the bridge.' They also found no flaws in the steel and concrete used in the bridge.


I met Gene Corley, NTHBs expert, at an engineering conference a number of years ago. Gene said that the initial design for the gusset plates contained incomplete calculations for stresses on the gusset plates. They accounted for 2 dimensional forces on the plates but not the 3 dimensional stresses placed on them by side supports and struts.



























 
#30 ·
I'm checking mine ASAP...a local buddy with a 2010 T100, <8000 KM's and always garage kept, salt free roads etc had his foot peg bolt shear this week. I'm at 14K KM's on my T100...and it came used at two years old from the Salt Belt....

Could this failure be due to galvanic corrosion between the steel bolt and alloy peg? Would a higher tensile bolt or stainless bolt of the same size be a good option?
 
#32 ·
On a Bonneville replacing the factory peg with Oberons or any brand of foot peg doesn't really make you much safer. Although it helps! Most Bonneville's break the clevis bolt. Adding a second clevis bolt as shown in several threads seems to be the best option. I found that even when you can't feel it the clevis bolt can be worn and moving. I had to remove mine to see the wear. Look at the picture on post 9 of this thread. The upper alignment dimple has worn where it has been moving. That clevis was probably loose for quite a while before it snapped. It wasn't loose enough the owner could feel it, but loose enough to wear. Mine was worn like that even though my bolt was not broken and seemed tight. A new clevis, a second bolt, and both bolts locktighted and properly tightened made me feel a lot safer.

Tom
 
#37 ·
If you can see evidence of movement between the mating surfaces then you should be aware that the bolt is not tight enough. This is a tension joint where the bolt should only experience a tension load. If the joint is loose, shear and bending loads can be born by the bolt leading the fatigue and ultimately fracture.

Making the joint stronger by adding additional bolts weakens the clevis and its mating structure and could mean that in the event of a dropped bike or hitting a curb, you could damage or bend the frame instead of breaking the foot peg. It's your choice.
 
#36 ·
Even better is to make sure that the bolt is tightened to the specified torque.

Putting in a stronger bolt could make the frame be the weak link in case of dropping the bike on the foot peg or striking an immovable object like a curb. Ask yourself if you would rather replace the foot peg or replace the frame.
 
#35 ·
This is a tension joint. The bolt passes through holes that are larger than the bolt thread major diameter and does not touch the foot peg clevis or its mating surface. There is no shear load on the bolt as long as the joint is tight at the design torque. Shear and bending loads are taken by the clevis and mating surface.
 
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