Let me preface by acknowledging that Smart Trainer does not imply smart buyer/rider …
So I bought a Saris H3 trainer and struggled quite a bit mounting my bike. Took me a while to figure out that because I have rear thru axle I don’t need the regular trainer skewer, but I do need to attach those bigger hub attachments that come with the trainer. Oh, and it turns out the Bontrager thru axle has this little switch level tool that’s nifty, but you can’t tighten the axle on the trainer with the tool on, because the level will bump against the trainer - and before I figured out how to remove that tool I bought a different thru axle from Saris, but turns out that’s not quite the same size as mine (12x165 vs 12x150) so the bike was wobbly and even after I screwed it on very, very tight it remained wobbly. Anyway, I finally figured out how to remove the Bontrager tool and that I can just use my Bontrager axle … But, it turns out that in the process of all this, I damaged the first few threads on the drive side of the bike frame needed to tighten the axle. So, what are my options at this point?
Replace the frame (yikes)?
Try to hammer the axle past the first few broken threads and hope the threads ‘catch’ after that?
anything else? I realize this sounds ridiculous, but would appreciate some advice. It has been a trying week. thank you!
Let me preface by acknowledging that Smart Trainer does not imply smart buyer/rider …
So I bought a Saris H3 trainer and struggled quite a bit mounting my bike. Took me a while to figure out that because I have rear thru axle I don’t need the regular trainer skewer, but I do need to attach those bigger hub attachments that come with the trainer. Oh, and it turns out the Bontrager thru axle has this little switch level tool that’s nifty, but you can’t tighten the axle on the trainer with the tool on, because the level will bump against the trainer - and before I figured out how to remove that tool I bought a different thru axle from Saris, but turns out that’s not quite the same size as mine (12x165 vs 12x150) so the bike was wobbly and even after I screwed it on very, very tight it remained wobbly. Anyway, I finally figured out how to remove the Bontrager tool and that I can just use my Bontrager axle … But, it turns out that in the process of all this, I damaged the first few threads on the drive side of the bike frame needed to tighten the axle. So, what are my options at this point?
Replace the frame (yikes)?
Try to hammer the axle past the first few broken threads and hope the threads ‘catch’ after that?
anything else? I realize this sounds ridiculous, but would appreciate some advice. It has been a trying week. thank you!
do NOT hammer it. take it to the shop and they can (most likely) retap the threads. (I’m assuming that you don’t have a tap and die toolset lying around your house).
I don’t know what your frame looks like but on my Roubaix the thru-axle actually goes through the frame on the threaded side.
If that is the case on your frame you have two easy options - one the right way and one the wrong way that you will probably get away with.
The right way is to buy the tap for that thread and run it through from the outside. Be careful to pick up the good threads when the tap starts. If you are cutting threads on the good side you either have the wrong tap or it was not started correctly. You should only cut material on the inside where the threads are rolled over.
The wrong way, and what I would do being a machinist (at one time) is to lube up the thru-axle and start it from the outside (the good side) and work in in and out until it rolls the threads back into position. Then carefully use a brillo-pad or some scotch-brite to polish out the threads a little bit since they will be rough.
However, considering that you made the mistake to start with tells me neither of these options are a good fit for you. In that case go to your LBS and let them fix it.
What model bike do you have? Many bikes have a replaceable thread* (it’s part of the rear derailleur hanger). Getting a new hanger should be fairly cheap, and is the “best” repair. Having a shop chase the damaged threads with a tap is the 2nd best option.
Not all TAs are created equal… the whole TA length and thread pitch is a mess, even more so than probably headset standards. That’s the reason why thru-axles come with the frame so they match. In all likelihood, the thread pitches mismatched and you strip the threads on the frame-side. Unfortunately, TA is not like QR skewers, they isn’t a universal one what will work on all frames. In any event in your case, you need to take it to a shop where they can repair the threads on the frame.
