Oh I seem to have messed up!

[RossG]

There I'd agree with you Monty homework is essential, I'd still argue Yose should get their act together and give a correct description of a component then you could make your own mind up as to whether it's worth making it fit.
Of course if it fits from the off, well....no problem. There's plenty of instances and long threads on cycle forums highlighting frame failures, many quite heated. I got very involved at one time in those discussions as did the owners of many well known cycle manufacturers, the end result was that welds on aluminium are nowhere near as strong as steel welds, which if done correctly are as strong as the components being joined.
It's because of all I learned through those long discussions I came to the final conclusion that stressing alloy welds is not a good idea, if engineers and cycle manufacturers give it the thumbs down that's me sold others can do as they wish.

 

[IanHurley]

My friend who recently bought a Yose rear hub motor asked them to confirm dimensions before purchase, they sent a PDF which confirmed 135mm but when it arrived it was several mm bigger and did not match the PDF in any way. Sorry Yose I think you are pulling the wool over purchasers eyes deliberately. Why they can't be honest about dimensions is beyond me. After many emails my friend was offered two options, £20 refund as compensation or return the item for a full refund. We made a jig to jack out the frame and did eventually make the Yose motor fit but Yose should be supplying the motor at the dimensions they say they do and not leave people to force the motor to fit. Would I recomend Yose to anyone? Absolutely not!

 

[MontyPAS]

My friend who recently bought a Yose rear hub motor asked them to confirm dimensions before purchase, they sent a PDF which confirmed 135mm but when it arrived it was several mm bigger and did not match the PDF in any way. Sorry Yose I think you are pulling the wool over purchasers eyes deliberately. Why they can't be honest about dimensions is beyond me. After many emails my friend was offered two options, £20 refund as compensation or return the item for a full refund. We made a jig to jack out the frame and did eventually make the Yose motor fit but Yose should be supplying the motor at the dimensions they say they do and not leave people to force the motor to fit. Would I recomend Yose to anyone? Absolutely not!

Sounds like you got a bargain. With a bit of DIY you managed to fit the hub and get a £20 refund. Problem solved.
I made a jig to stretch my frame.....
It's called a bottle jack.
Well done with fitting the Yose kit. They work very well. Considering what they cost

 

[MontyPAS]

There I'd agree with you Monty homework is essential, I'd still argue Yose should get their act together and give a correct description of a component then you could make your own mind up as to whether it's worth making it fit.
Of course if it fits from the off, well....no problem. There's plenty of instances and long threads on cycle forums highlighting frame failures, many quite heated. I got very involved at one time in those discussions as did the owners of many well known cycle manufacturers, the end result was that welds on aluminium are nowhere near as strong as steel welds, which if done correctly are as strong as the components being joined.
It's because of all I learned through those long discussions I came to the final conclusion that stressing alloy welds is not a good idea, if engineers and cycle manufacturers give it the thumbs down that's me sold others can do as they wish.

From experience, I have found that welds, be they alloy or steel are usually stronger than the material they are joining. I have done close to 800 winter miles after stretching a secondhand carrera from around 10mm, no issues are apparent. Think you will find a lot of members have done the same without issue.
Other opinions are available...

 

[Adgerolla]

Thank you all for your knowledgeable and helpful comments. A refreshing change to some of the impatient or dismissive comments I have witnessed on some other specialist interest forums! I can see there is not a total consensus. In the end I remembered my son still had an unused Specialised Rockhopper I gave him so I reclaimed it to experiment with stretching the rear drop out, rather than ruin my GT . It seemed successful using a threaded bar and two large washers. So I went ahead with the build and so far after a couple of road tests the bike is performing really well. Bearing in mind all the comments I will check for signs of stress fractures before and after every ride until it seems unecessary. I added a torque arm for security as well as using the anti rotatio washers. The Yose kit is very good other than this particular issue but they should really give people the correct info. Thanks again guys. See you on the Devon bridleways and commons! PS I also fitted aftermarket hydraulic brake sensors so I could retain the Shimano combined gearchange/brake set up. Work a charm!

 

[MontyPAS]

Thank you all for your knowledgeable and helpful comments. A refreshing change to some of the impatient or dismissive comments I have witnessed on some other specialist interest forums! I can see there is not a total consensus. In the end I remembered my son still had an unused Specialised Rockhopper I gave him so I reclaimed it to experiment with stretching the rear drop out, rather than ruin my GT . It seemed successful using a threaded bar and two large washers. So I went ahead with the build and so far after a couple of road tests the bike is performing really well. Bearing in mind all the comments I will check for signs of stress fractures before and after every ride until it seems unecessary. I added a torque arm for security as well as using the anti rotatio washers. The Yose kit is very good other than this particular issue but they should really give people the correct info. Thanks again guys. See you on the Devon bridleways and commons! PS I also fitted aftermarket hydraulic brake sensors so I could retain the Shimano combined gearchange/brake set up. Work a charm!

Looks good. Glad you persevered and got it sorted

 

[harrys]

I thought the Rockhopper was alloy frame? Newer ones anyway,

 

[RossG]

From experience, I have found that welds, be they alloy or steel are usually stronger than the material they are joining. I have done close to 800 winter miles after stretching a secondhand carrera from around 10mm, no issues are apparent. Think you will find a lot of members have done the same without issue.
Other opinions are available...

You're quite right Monty members do on occasions talk of stretching frames with success, but then they're hardly likely to comment if they made a mess-up of it. We all like to talk of our endeavours and success's, less likely to mention failures...not too good for our street cred
Seriously though I've never felt the need to hammer a square peg in a round hole but to each their own...

 

[Adgerolla]

I thought the Rockhopper was alloy frame? Newer ones anyway,

Yes, it is. So far so good!

 

[D C]

There's lots of practical evidence from folk who've stretched their frames with no adverse effect but of course it can only be theories from those who've never done it.
Thank goodness for those who try new things.
I think most folk on here would report back if they had a problem, it's that sort of a forum, most of us are here to help and advise each other and to prevent others from making the same mistakes that we may have made .

 

[Adgerolla]

There's lots of practical evidence from folk who've stretched their frames with no adverse effect but of course it can only be theories from those who've never done it.
Thank goodness for those who try new things.
I think most folk on here would report back if they had a problem, it's that sort of a forum, most of us are here to help and advise each other and to prevent others from making the same mistakes that we may have made .

Yes, I tend to want to share mistakes as well as successes. I think your comment is a celebration of all that is best in this forum!

 

[RossG]

There's lots of practical evidence from folk who've stretched their frames with no adverse effect but of course it can only be theories from those who've never done it.
Thank goodness for those who try new things.
I think most folk on here would report back if they had a problem, it's that sort of a forum, most of us are here to help and advise each other and to prevent others from making the same mistakes that we may have made .

That's why I said earlier that when someone makes a ralls-up of something they've done wrong they tend to keep schtum and not look silly, human nature really. When something goes well you want to share it with others so they might benefit as well. I have a mate who's frame cracked at a weld point when he stretched the rear stays to fit a wheel that was never meant to go in, hence I pass it on that a frame can crack if stretched.
It doesn't matter if a hundred people have done it, I know otherwise. But as I say to each their own.

 

[Adgerolla]

Well, yes, I would have preferred not to have to adapt the bike to fit the motor. Clearly there is some risk in stretching alloy . Who knows if there was a weakness present in your mates weld or if he was not as careful as he could have been ( no critism intended) . Your warning was as useful as the comments suggesting it would probably be ok as it helped me to make an informed choice about risk and be very careful in the stretching process. I am also obsessively monitoring the rear of the bike before and after each ride. If I get any hint of deterioration I promise to report it. In the meantime , I have a bike which is lighter, faster and more fun than my second hand Mountain sport. Now...what about the voilmart 500 kits?.......

 

[RossG]

It just depends on what your approach is to a problem is. Let's put it this way if you purchased a frame & wheels from a professional bike company like say Evans or wiggle, went to pick the items up and asked the assistant to pop the wheels into the frame for easier transport to your car. The guy then lays the frame on it's side, puts his size 11 boot on one dropout yanks the other side up and while going red if the face tells his mate to shove the wheel in quick like.
Well of course that's not going to happen is it...now ask yourself why not ? Nuff said really, but if it works for you that's all that matters. That then poses the question would you buy that bike frame you saw the mechanic stretching.......myself, no I would not.

 

[jimriley]

It just depends on what your approach is to a problem is. Let's put it this way if you purchased a frame & wheels from a professional bike company like say Evans or wiggle, went to pick the items up and asked the assistant to pop the wheels into the frame for easier transport to your car. The guy then lays the frame on it's side, puts his size 11 boot on one dropout yanks the other side up and while going red if the face tells his mate to shove the wheel in quick like.
Well of course that's not going to happen is it...now ask yourself why not ? Nuff said really, but if it works for you that's all that matters. That then poses the question would you buy that bike frame you saw the mechanic stretching.......myself, no I would not.

How much was your mate trying to stretch his frame? Crucial bit of info. 10mm or 50mm, would make a difference to what you could do without cracking the frame.

 

[RossG]

I don't know TBH but I know it wrecked his frame though. It's not so much a case of a frame suddenly snapping in two, more a matter of stress fractures that can't be seen with the naked eye. Aircraft don't suddenly fall apart in the sky luckily but they're regularly x-rayed for signs of fracture because of what they have to go through.
Folding bikes are a good example of what I'm talking about, now where would you say the weakest point on a folder is ? the hinge obviously. Well strangely enough it's not it's the welds that join the hinge to the frame that are most likely to fail, have a search for the Trek folding bike frame catastrophes it nearly ruined that company.
Steel welds are much stronger than alloy joins plus steel behaves much better than alloy when under stress, not that anyone would but imagine stretching a carbon fibre frame....SNAP !

 

[vfr400]

I don't know TBH but I know it wrecked his frame though. It's not so much a case of a frame suddenly snapping in two, more a matter of stress fractures that can't be seen with the naked eye. Aircraft don't suddenly fall apart in the sky luckily but they're regularly x-rayed for signs of fracture because of what they have to go through.
Folding bikes are a good example of what I'm talking about, now where would you say the weakest point on a folder is ? the hinge obviously. Well strangely enough it's not it's the welds that join the hinge to the frame that are most likely to fail, have a search for the Trek folding bike frame catastrophes it nearly ruined that company.
Steel welds are much stronger than alloy joins plus steel behaves much better than alloy when under stress, not that anyone would but imagine stretching a carbon fibre frame....SNAP !

Sorry, I call complete ball-cox. Which welds do you say failed?

 

[RossG]

I never saw the frame in question but I believe it was at the seat end, I have seen the same thing happen even on steel frames...and you haven't with all your experience ? I don't believe that sorry vfr it happens and you know it.

Here's another one to ponder over, that same friend of mine (him again) had a mishap when we were out on a cycle run some years ago. We were flying down a hill touching 40 odd on pushbikes and when we got to the bottom he pulled up to a sharp stop and pointed to his front light. The bracket holding the light had snapped off and the light was dangling touching the front wheel...a close shave indeed could have been nasty.
Taking a close look I saw it was a home-brew job fashioned out of aluminium bent into shape, it had failed I believe because of stress fractures and continual vibration that would occur as a result of a fixture holding an object at one point of attachment.
That's exactly why quality alloy folding bikes now have abutments welded into the frames at the hinges for added strength, I was one of the people who campaigned to get that done after much discussion with manufactures.
Were you aware Halfords stopped selling Carrera Banshees because of stress fractures in the chain stays due to poor design & welding, I'm guessing not but that's why I sold mine quick but did inform the buyer of the problems.
I stand by what I say, I buy shoes that fit I buy wheels that fit..no problems at all.

 

[vfr400]

I never saw the frame in question but I believe it was at the seat end, I have seen the same thing happen even on steel frames...and you haven't with all your experience ? I don't believe that sorry vfr it happens and you know it.

Here's another one to ponder over, that same friend of mine (him again) had a mishap when we were out on a cycle run some years ago. We were flying down a hill touching 40 odd on pushbikes and when we got to the bottom he pulled up to a sharp stop and pointed to his front light. The bracket holding the light had snapped off and the light was dangling touching the front wheel...a close shave indeed could have been nasty.
Taking a close look I saw it was a home-brew job fashioned out of aluminium bent into shape, it had failed I believe because of stress fractures and continual vibration that would occur as a result of a fixture holding an object at one point of attachment.
That's exactly why quality alloy folding bikes now have abutments welded into the frames at the hinges for added strength, I was one of the people who campaigned to get that done after much discussion with manufactures.
Were you aware Halfords stopped selling Carrera Banshees because of stress fractures in the chain stays due to poor design & welding, I'm guessing not but that's why I sold mine quick but did inform the buyer of the problems.
I stand by what I say, I buy shoes that fit I buy wheels that fit..no problems at all.

The seat end is completely unstressed by any motor because there are braces eithe side that would take any sideways stress. The seat stay welds only deal with the up and down stresses as you go over bumps. if you never saw it, what makes you think that the stretching caused it?

I've seen (owned) an old road bike that had a detatched seat-stay weld on one side. Even with my 100kg riding on it and my front motor conversion (Q70), it didn't make any difference. I was going to get it welded, but in the end I never bothered. I dont think the next owner did either.

 

[harrys]

While this has nothing to do with stressing aluminum. as an owner of several folding bikes, strength of welds has been a concern. I hadn't heard about the folding Treks, but Tern had a recall several years ago. Bad quality in welding? I'm not a mechanical guy, but it would seem some gussets ought to be in there.