Are my Middleburn RS2s knackered?

[provdes]

Hello, this is my only my second post, but I've seen some very good advice on here, so I am wondering if there are any Middleburn fans that can help.

I recently purchased some very nice Middleburn RS2. I took the spider off to clean them up and when reinstalling it, I carefully tightened each of the 4 bolts that hold the spider on, but one of them just turns and feels like the thread has been stripped.

Are these shot? Should I just whack some threadlock in there and gently tighten as far as I can and hope for the best?

Or is a repair possible?

I have tightened the others very lightly just in case, but does anyone have a manual with the torque settings for these bolts? (or does torque go out the window with old cranks like this)

 

[Frankenorange]

Two ways to repair. One is to drill the hole and tap a new thread, the next size up. Whatever you are mounting will need to have a clearance hole drilled in it to suit the larger screw. The other way is installling a helicoil so you maintain the same screw size. That involves drilling a hole, tapping the hole for the helicoil and then inserting the helicoil with a special little tool. All simple to do at home, if you have the right kit, or a local machine shop should do it for a few beers.

 

[Rebikecumbria]

Two ways to repair. One is to drill the hole and tap a new thread, the next size up. Whatever you are mounting will need to have a clearance hole drilled in it to suit the larger screw. The other way is installling a helicoil so you maintain the same screw size. That involves drilling a hole, tapping the hole for the helicoil and then inserting the helicoil with a special little tool. All simple to do at home, if you have the right kit, or a local machine shop should do it for a few beers.

aye what @Frankenorange said hellicoils are fabulous things - i always get my local handy engineering company to do mine because they've done a lot of hellicoiling and experts at it so i would recommend getting someone who's done it before as can be fiddly and by the time youve bought hellicoil kit ect might aswell get someone whos already got all the kit to do it - unless your hellicoiling on the regs

the ones i ve had done have been spot on and many will say hellicoils are stronger than the original threads which i can believe as never had a problem with them even under heavy use

 

[hamster]

many will say hellicoils are stronger than the original threads which i can believe as never had a problem with them even under heavy use

Too right. I used to work for an aerospace company (electrical generators for jet engines), we never put machine screws into aluminium directly, always into helicoils.

 

[provdes]

Thanks! I'll do some research, helicoil kits look cheap enough, but I don't want to ruin my cranks!

 

[Rebikecumbria]

Thanks! I'll do some research, helicoil kits look cheap enough, but I don't want to ruin my cranks!

this is why i got some pro hellicoilists to do my jobs as didnt want to ruin expensive or unobtainable again parts ; )

 

[Rebikecumbria]

this is why i got some pro hellicoilists to do my jobs as didnt want to ruin expensive or unobtainable again parts ; )

also was cheap as chips each time

 

[Frankenorange]

Thanks! I'll do some research, helicoil kits look cheap enough, but I don't want to ruin my cranks!

If you have experience and a decent pillar drill with clamps and packing, or some kind of jig, at home then you can do it. If you have neither then please do take it to a machine shop as the holes and threads need to be tiptop. The helicoil fitting itself is a doddle.
If you have a car/bike engine machinist nearby then they are a good bet. It is bread and butter for them and are geared up for 1 off jobs, like your crank. Some machine shops are more into 100-1000 off and those might not be interested. All depends though as you might find the boss is into cycling.

 

[BIGBOYZJUNK]

Get yourself a helicoil set and bobs ya uncle

 

[Once A Hero]

That’s one of the problems with the early Middleburn cranks, especially after all these years, the crank either cracks, or the tiny screw threads get stripped.

I dare not remove the spider for that very reason if I can help it.

I have a set of RS-3s’ on one of my bikes but I think one of the tiny screws holding the spider on isn’t doing much - but the other 3 are good. Best to leave alone!

I’ve got another set I was intending to sell, but the non-drive side crank has a nice crack in it. I suppose I could try and remove the spider, as it may be of use to someone, and if the threads strip then it won’t matter as the cranks themselves are toast.

Sadly it’s just the way they go