Transmission database - for all your crank / bb / bottom bracket questions

Not on the removable plastic cover but on the drive-side one. The cups just have "Drive Side" and "Non Drive Side" and some torque values. Everything else has been scraped off. The 43-06 is on the cups.

I could do lots of things but I want to find out what the fuck setup this is so I can document it before sacrificing it to the devil.

I think I've found what it is, or at least what it looks like...

It's a Truvativ GXP BB

http://www.tredz.co.uk/.Truvativ-GXP-BlackBox-MTB-BB-Cups-w-Ceramic-Bearings-and-Press-Fit-Adaptor-BB92_26154.htm

It looks like it's one of these...

http://www.ebay.com/itm/SRAM-TRUVATIV-GXP-BOTTOM-BRACKET-BB-EXTERNAL-CUPS-RACE-MOUNTAIN-ENGLISH-68-73-mm/192083038216

Feckin' Halfords appear to sell them:
http://www.halfords.com/cycling/bike-parts/gears-drivetrain-cables/truvativ-bottom-bracket-gxp-team-cups-english

Still GXP though.

Got calipers? Check the ID of the bearings. Failing which, if you put one on top of the other you can see if one is smaller.

But hurry: I'm on my way over with a flamethrower.

And C4.

And a very big hammer.

I'm embarrassed, I have, what I'm sure is a really stupid question.

I have a campy record pista chainset, like this one http://www.wiggle.co.uk/campagnolo-record-pista-track-chainset/

I want to put a new chainring on it, will a sugino zen chainring fit? are all 5 arm cranks the same standard ?

General Googling hasn't been very helpful.

Cheers.

Morning all, quick reassurance required....

Is my ultegra 6600 front mech (double) going to play nice with the new tiagra 4700 chainset I picked up on the cheap? Using google on phone has given me nowt.

Yes, campy pista is 144bcd and sugino zen chainring is 144bcd so they are compatible with each other.

So in future, if you want to change your chainring or crankset, you just have to make sure that the chainring and crankset are the same bcd for them to be compatible with each other.

Hope this helps a bit, I'm dire at explaining things I'm afraid.

Has this been resolved thrown in a corner yet?

Funny, I read this thread this morning and thought about posting an update.

An update.

The GXP BB from hell is...

Were the cranks Mega Exo?

Was the GXP BB a bodge?

Will Ron tell Steve how he really feels?

The suspense is killing me

I'm going to open a museum where people can theorise about the crank and BB identity.

I'm sure it's a GXP BB but perhaps it has had a bearing swap? The cranks I think are FSA Mega Exo of some sort.

Dibs!

Just in case anyone was interested.... I've just fitted a Stronglight 49D to my Mercian Superlight. This was on the bike previously, but had a Stronglight 118 loose ball BB fitted, which gave a chainline of 44mm - about 2mm more than required.

With a bit of trial and error, it appears that a standard 113 JIS Cartridge BB gives a 42.5mm chainline, with 1mm of clearance between the chainset and rhs bb cup, which is about as close as you're going to get to the 'perfect' 42mm required.

Sounds good:

• to bring the ring inboard by 2mm, requires a 4mm shorter BB;
  
• which gets us to 114mm;
  
• -2mm to convert from ISO to JIS is 112mm.
  
  

Maybe you could lose the extra 0.5mm with magnets?

I've got a pair of sora triple cranks that I'm looking at converting to a 46/30 double with a spa cycles ring.

If I understand correctly I should be able remove the big ring, replace the 110bcd middle ring with a 46t or a 44t from spa, and leave the original shimano 30t inner.

Is there anything I should look out for? I assume I'll be able to compensate for the change in chainline with bb spacers, but not sure if there's something that I've missed.

I bought SG75s some time ago and I might need a matching bottom bracket soon.
I'm about to order the CBB-SG75 but I got word that Sugino uses proprietary taper axles. Is that a new thing or have they been using them since forever?

is this pressfit GXP BB what I need to fit Rival 22 GXP chainset in 86.5mm shimano BB86 shell on a Genesis Volare 10 853 2014?

Quite confused by pressfit and ideally would like to keep these cranks.

Thanks

Hi Gang, I'd like to switch up an early 90's roadbike from a double to a triple chainset. I tried the new triple chainset with the the original bottom bracket and the chainline was way out, with the whole drive side sitting way too far from the frame. So the question is how do I go about finding a suitable bottom bracket which will allow the chainrings to be positioned closer to the bottom bracket shell? Presumably I need a bottom bracket with narrower spindle? Any help would be really appreciated, cheers!

I tried the new triple chainset with the the original bottom bracket and the chainline was way out, with the whole drive side sitting way too far from the frame.

Something (beyond the width of the spindle) sounds wrong.

Was the NDS the same distance from the frame as the DS?

What is the chainset and what BB did you try?

Alright Jim, thanks for the response, I'm not sure if the spacing between the cranks on the drive and non-drive side was different, but the gap on the drive side was definitely unusually large. I think I've made some progress though, by changing the BB for a 103mm one the spacing now seems ok and the front mech I have which is definitely for triple rings seems to throw far enough to reach all three rings. In fact the problem I seem to be having now is that after each shift the cage seems to be too far outward. It was late when I was trying to set the trim though, so will give it another go today.

To answer your other question the cranks are some random Sugino ones with FSA chainrings. An issue I'm slightly unclear on is whether there could be a problem trying to marry this particluar chainset with the cassette I have which is just a modern Shimano 8 speed one. Can you encounter problems with a triple chainset with rings for a 10 speed set up and an 8 speed cassette? Any thoughts much appreciated!