bikeperson45 Posted April 6, 2018 Report Share Posted April 6, 2018 My situation at the moment is the other day my chain snapped, I didn't have a chain tool on me and wanted to be able to ride after work so I lazied out and took it to a local bike shop at lunch. They said cool, we'll have it ready by 5, so I thought perfect, after work ride strategy intact. Five hours later, I've pick up the bike and the guy says it's on there and that he moved the wheel back in the dropouts a bit so had to stick two washers so the brake lined up properly. Cool beans I thought. I go for a ride and the brake snaps into pieces, in hindsight because those two insignificant pressures put more pressure on the brake. I was so paranoid about the brake snapping I was only playing a two foot wall, so nothing major. So the question is, would I be right in saying you owe me a brake to the bike shop? Quote Link to comment Share on other sites More sharing options...
AndyT Posted April 6, 2018 Report Share Posted April 6, 2018 What kind of brake and where did it snap, pictures???? Quote Link to comment Share on other sites More sharing options...
bikeperson45 Posted April 7, 2018 Author Report Share Posted April 7, 2018 (edited) 9 hours ago, AndyT said: What kind of brake and where did it snap, pictures???? Shimano Saint rear brake, bike's over at work now but it snapped at both mounts at the same time... Red lines are the cracks, snapped on both sides too. Edited April 7, 2018 by bikeperson45 Quote Link to comment Share on other sites More sharing options...
bing Posted April 7, 2018 Report Share Posted April 7, 2018 I'd make them replace the brake 1 Quote Link to comment Share on other sites More sharing options...
Topsy Posted April 7, 2018 Report Share Posted April 7, 2018 Yeah that doesn't seem normal.. Quote Link to comment Share on other sites More sharing options...
forteh Posted April 9, 2018 Report Share Posted April 9, 2018 If they put thicker/more packing under one of the bolts it would put uneven forces on the casting and put stress raisers in there. As far as I'm aware, there shouldn't be any significant requirement to move the caliper because the rear axle has moved backwards in the dropouts, there is plenty of contact with the braking surface and the pads. If the wheel had moved forwards then it's feasible that the rotor may have been catching on the caliper (if you're using an oversized rotor like a hope 183 when the caliper is designed for a 180) in which case shimming the caliper up by a couple of mm would work but it should be proper square shims not washers (ie: the hope IS mount shims, they're lasercut from flat sheet rather than washers that are punched and subsequently not as flat). New caliper time, I suspect that they will try to wriggle out of it though. Get some photos of the caliper/bolt setup Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted April 9, 2018 Report Share Posted April 9, 2018 In fairness, a number of these have been broken through "normal" trials use in the past so you might struggle to prove the cause (though obviously I hope you're able to get it sorted). I suspect the shock loading in alternate directions is a little outside the design parameters of the mounting points, which is a shame as when they're working those Saint calipers aren't a bad bit of kit. Quote Link to comment Share on other sites More sharing options...
bikeperson45 Posted April 9, 2018 Author Report Share Posted April 9, 2018 Thanks for the input - I might have managed to get lucky with this shop, took it back Saturday and explained to the manager and he went with the 'if we're the last people to touch it and that happened something's not right' stance so it's with them again and he's looking to replace it. They'd definitely moved the wheel backwards thought it didn't look like anything significant to warrant fiddling with the brake. Hopefully that's best case scenario if they get a new one on there and it all looks good. I hadn't heard of Saints braking, I just remember Danny Mac using ten years ago and thought if it's good enough for that guy... 2 Quote Link to comment Share on other sites More sharing options...
Mark W Posted April 9, 2018 Report Share Posted April 9, 2018 Seems a few of the ones that broke broke because they were being used loose, or being used with shit adaptors that were the part that broke first. For what it's worth, all the post mount calipers I've used from Hope, Shimano and Magura have had shims under them without causing them to snap. For example, you can't use a Hope Trial Zone post mount caliper with a Hope 160mm IS frame/fork to Post Mount adaptor without shims because the caliper hits the adaptor otherwise. If the shims weren't great, or weren't equal sizes, then that could lead to some bad stuff going down. Similarly if they'd worked loose then that wouldn't help either. Quote Link to comment Share on other sites More sharing options...
Dman Posted April 9, 2018 Report Share Posted April 9, 2018 Could overtightening cause it? Quote Link to comment Share on other sites More sharing options...
swill Posted April 11, 2018 Report Share Posted April 11, 2018 Not likely unless it was already off square or theyre countersunk bolts that forced the mount to deform. Though I suspect they were flat faced bolts. Which if the shims caused the caliper to sit out of alignment as said above could cause internal stresses which after loading further through riding, could have caused strain and lead tofailure. Though theoretically if you tightened it enough the alloy (whatever it is), the caliper is made out of, is obviously going to be lower in terms of mechanical properties than the presumably ms bolt. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.