[w00dy]

For any of you long time Mini or Race Link riders out there. I think I improved on the suspension system today. The two tension links normally attach to the front triangle via two button head cap screws. Every other part of the suspension has a through bolt and a nylock nut on the other end. The two separate bolts are the only pieces of the system I've ever seen fail. I've seen them break, and I've personally had one bend after backing out. I had the bike apart to replace some cruddy bearings and I noticed that you can see through the frame where these two bolts thread in.
I took a chance and drilled the threads out of the frame and mounted a single long bolt in place of the two. I've got a nylock nut on there and I don't have to worry about these troublesome little bolts again.

Please excuse the hazy cell phone pic.

Tips for getting it straight:
The bolts in the rear end are all 8mm, so these threads will have a minor diameter of about 6.5mm.
I passed a drill bit through first which was about 0.290" (7.37mm). It's intermediate size will follow the path of least resistance and just knock the tops off the threads. After this the hole is large enough to slide the back end of a reamer in. I passed the reamer through backwards so it's shank acted as a guide to keep it straight. This isn't the best thing for a reamer, but the frame is a hell of a lot more expensive. A 5/16" (7.94mm) reamer worked perfectly for me. It's a little undersized, but so is a standard cap screw shank. The fit was great.
As for the bolt:
A high grade M8 x 120mm long bolt will have about 100mm of unthreaded shank. This is just enough to pass through the links and frame. Put a nut on, cut the excess, and you're golden.

 

[IH8Rice]

why didnt it originally come with a nylon nut or a through bolt on it like you installed?

 

[w00dy]

Don't know. Weight savings or chain clearance probably.

 

[pastcaring]

Not the first time I've seen this done, but still a very good mod for rl/ml.

 

[Sandwich]

why didnt it originally come with a nylon nut or a through bolt on it like you installed?

maybe weight? you're talking about ~2" or so of bolt that's just sitting there in the middle of the tube. Maybe so that you don't have to fully disassemble the link to get to one side? Some loctite MAY be able to fix it, but you still have to keep your eye on it.

I had to check those bolts almost every ride, so I'm betting this mod is pretty solid.

 

[Sverre]

I´ve had a few link bolts snapped of right there on my RL and thought about doing this myself, but Doc, who designed the bike, did not recommend doing it. Can´t remember why though. Long time ago.
My frame does not have a see tru hole between the bolts. #67

 

[xy9ine]

you still have your rl, sverre? that was a sweet build.

 

[w00dy]

My frame does not have a see tru hole between the bolts. #67

Not with snapped off bolts in there it doesn't.

Maybe the early versions just had lugs welded to the outside of the tube. I can see how that would make it hard to bore a nice straight hole through.

 

[boogenman]

ohh Dave u so smart....

 

[w00dy]

That's what my Mama tells me.

 

[Sverre]

Yep I still got me frame. Not sellin´that. It´s been collecting dust for a while, but I´ll rebuild here some day for sure.
Hmm.. Maybe my frame did have a see tru hole.. Can´t quite say so long ago I´ve done some work on it. I took the broken bolts out before mounting new ones off course.

 

[w00dy]

A little bird told me there are three reasons:
Weight, chain clearance (more so on the RL than the mini), and the availability of high grade bolts with a low profile head.

I guess bolts of the proper dimensions and grade are only common with a socket (allen) head. That's too big, and if you cut it down there's no socket left.

 

[Sverre]

Nah. The original bolts that came with my frame was a hi grade hexagon bolt that was machened down. When I snapped´em I replaced them with a hi grade allen boly that I machined dow a bit. Still had plenty of insertion for the allen key.