Stormy85

Hi everyone

So I managed to pick up an old 2007 Giant Trance 1 frame for 1€ and want to bring it back to life. Unfortunately, I wasn't aware that sourcing the shock bolts would be so difficult. I have read that it would be better to use the Giant specific bolts designed for the frame but having reached out to several LBS there is no chance of getting only the bolts. One shop quoted me 119€ for the bearing set which apparently has the bolts but that would blow my budget out of the water.

Do you guys have any suggestion on possible alternatives? I cant believe that the frame is essentially unusable unless you are able to find factory bolts.

jimc101

Guess you found out why it was cheap! old bike with proprietary parts are problematic, you seem to have already found the solution, your decision not to go with it.

Looking at a kit, it seems have a few other bits, on the basis that these are included, maybe it won't be such a bad price if they are needed as well?

cxwrench

Believe it.

Stormy85

What puzzles me is that the bolts don't look to be particularly special. The upper bolt mounts directly into the swingarm, is it called that? I would assume that a standard m6x30 bolt with a washer would do the same job.
The lower bolt goes completely through, hence a bolt with some washers and a nut would also do the job. If I was to buy some generic bolts how long would the smooth part (shaft) need to be? I am asking because I have a Lapierre 410, which has a shock bolt, that has a very small shaft. I would even say that the bushing is entirely resting on the threads of the bolt.

Just stumbled upon a generic Shimano brake caliper bolt (m6x32,1) and when compared to the original bolt in the picture (the one on top) i can't see any noticeable difference. I would even say that the shaft is longer on the Shimano bolt. Would the material be different?

redshift1

I tend to agree with you that factory bolt replacement should be possible with non-original fasteners. I have no experience with mountain bikes but assume you are talking about the bolts holding the bellcrank to the swingarm to the rear and to the shock in front, just above the bottom bracket. Check the heads of the factory bolts for markings that indicate grade. If none, I would use the strongest bolts you can obtain, at least grade 8 if these are imperial bolts or else 12.9 if they are metric. Provided you measure the bolt diameters accurately ( vernier caliper ) so that you have the correct play between parts, I can't see a problem. Your question about how long should the smooth part of the bolt be ( technically called the grip length ) is a good one, often ignored by everyone including manufacturers. You do not want the threads themselves being loaded in shear against the parts being secured, otherwise you have the workings of a low speed mill every time the suspension acts. Have the smooth part all the way through the assembly, with the threads only being there at the very end to allow the nut to fasten. If the factory bolts were special lengths, you may have to shorten the threads and perhaps add some washers on the bolts that you are able to get from a fastener specialist ( bolt shop ).

Crankycrank

Hard to tell from the photo but that Shimano bolt may have a smaller diameter shoulder compared to the threads than the others which if true would be a no go for a replacement.

Stormy85

I mean the bolts that are used to mount the rear shock to the bellcrank (thank you) at the top and underneath the downtube in front of the bottom bracket. I have bought some standard metric bolts in M6x50 and M6x70 (12.9 grade) and have shortened them. This way the grip length is almost the entire length of the bushing. In comparison to my Lapierre, the grip length is far longer, so if it works on the Lapierre, why shouldn't it work on the Giant.