OK, bit of an incident with my frame and a shimano xt BB cup = equalling stripped threads. MY LBS and Trek are sorting me out a new frame, (god bless them!) but want to know which external BB has the longest threaded bit to stick inside the BB area. Running SLX cranks …

Was looking @ the RF Diabolus downhill BB, but a bit weary of RF quality following on from ISIS.
Suggestions and sarky coments all welcome…

I think the RF are the longest. As for how good they are – sometimes good or sometimes appalling.

Mick, personally I would be looking for material spec before thread length. I know it impossible to know what manufacturers use but I would much prefer something made out of HE15 with a short thread length than a HE30 one with a long thread.

Also you have to take into consideration tolerances of the two threads involved. If you have a frame with a thread at its upper limit and a BB at the lower limit then you may have problems with the thread stripping.

Just something else for you to consider… 😯

New Saint have longer threads. £35 on CRC.

However, surely it wasn’t installed properly the first time?

Mick I’d go for a set of Phil Wood HTII cups as they’re made from Stainless and insert them with some Rock N Roll assembly grease. On saying that maybe its too high quality for a Trek frame 🙂

Runs as fast as he can shouting taxi……………..

rib check!! Yeap, still intact, you’re a funny guy Shel!

Booooom Tish

I keep wondering why Shimano make you add spacers behind the cups to move them out, rather than on the axle to move the crank out.

I have a plan.

brant – Member

I keep wondering why Shimano make you add spacers behind the cups to move them out, rather than on the axle to move the crank out

To keep the bearings as wide as possible to support the axle I suppose…

To keep the bearings as wide as possible to support the axle I suppose…

There would be more cantilevered distance if you shimmed outside, but peak forces can’t increase by *much* you’d have thought.

hello Brant, I’ve wondered the same thing – I’ll take two sets please

(? could maybe introduce some additonal screen for bearing seals too ??)

(no, I haven’t thought that through in any way)

(no, I haven’t thought that through in any way)

I have 😉

I’ll take two sets please

OK, three then – since you’ve thought about it

Yes, Brant, I’ll have some too. Good idea. Please make them shiny – that’s more important than bearing seals surely 🙂

Mick, I had the same, threads on my heckler stripped, allegedly due to the short XT threads, ended up with warranty new front end and I check the BB is tight often.

CK BBs can be gotten cheap, email me or snakey.

brant – Member

I keep wondering why Shimano make you add spacers behind the cups to move them out, rather than on the axle to move the crank out.

I have a plan.

I ditched the spacers on my HTII BB / Saint cranks on my BMX cruiser and used Raceface spacers to improve the chainline / remove play. The cranks broke but that’s another story…

Just make sure the cups are installed properly. These instances must be extremely rare. (tho I can see not rare for the op)

how many EX8s have you had now Mick? should get a 09 this time?

Scruff, cheers for that mate. Was looking for either a hope or CK option.
RD, Just the one! (until now).

Saint 83mm cups?

When I had the same problem (stripped drive side thread, interestingly also on a trek) I used the diabolous BB and just one spacer (i.e. as much thread in the frame as possible) and all was fine.

hmmmmmmmmmm……………….

given how strong threaded joints are i’d not be too worried about the lenhgth of the thread in the frame. the only way it could strip surely is if you let it losen ?

brant – Member

I keep wondering why Shimano make you add spacers behind the cups to move them out, rather than on the axle to move the crank out

When you look at the axle, the place where the bearings sit ( ie the ends) are a slightly larger diameter than the rest of the axle. Can’t remember off the top of my head, but I don’t think the bulge isn’t that long. So if you did use spacers on the axle instead of behind the cups the bearings would then be sitting on the transitional diameter part of the axle…