GT Team Avalanche BB width for 1x commuter

[kicks66]

Hi there,

I'm looking to build up a GT team avalanche (think its a 1990 model). One thing that I'm questioning a lot is what is the right size bottom bracket to get for it?

I want to run it as 1x commuter, with either 8/9/10 speed.

How would I go about working what BB to get? I'm concerned about whether there will be issues with it hitting into the chain stay?

 

[PhillB]

A lot depends on the crankset you are going to use on it. It is a 73mm British threaded shell. I think I ended up using a 127mm spindle on mine, to fir a Shimano M730 Crankset.

 

[27motorhead]

I see @PhillB has helped point you in the right direction.

Will 100% depend on chainset. Do you have one to hand or will you buy one? This will determine the required length of the axle.

But as Phill as stated the start point will be a 73mm shell with English threads (right hand thread on non-drive side and left hand thread on drive side. This is the most common, don't worry!)

 

[Black_puma]

Hi there,

I'm looking to build up a GT team avalanche (think its a 1990 model). One thing that I'm questioning a lot is what is the right size bottom bracket to get for it?

I want to run it as 1x commuter, with either 8/9/10 speed.

How would I go about working what BB to get? I'm concerned about whether there will be issues with it hitting into the chain stay?

It's a steel frame so it would be a 68mm BB shell.

 

[ishaw]

If you are going to run 1x, are you looking to use an older crank or go modern? If the latter, any hollowtech 2 (ht2) BB will work with ht2 cranks. You just need to run the spacer washers to take up the 68mm to 73mm (by design, not a bodge). If you are using an older crank/BB, the BB width is usually crank specific to a large degree, but running 1x may change that depending on the chain line you get with the single ring.

 

[elite504]

It's a steel frame so it would be a 68mm BB shell.

Nope. Tange prestige concept. Ovalised down and seat tubes (a bit like Columbus Max).
The BB shell with was one of the components that stopped it having full XT. M730 BB wasn't available in a 73mm shell width.
As others have said, crank will dictate. Phil B is right on the money.
You'd think with it being a 73mm shell you could probably shorten the BB axle for a better chainline, but the chainstays are large and there is not a lot of clearance between the says and the rings.

 

[Black_puma]

Nope. Tange prestige concept. Ovalised down and seat tubes (a bit like Columbus Max).
The BB shell with was one of the components that stopped it having full XT. M730 BB wasn't available in a 73mm shell width.
As others have said, crank will dictate. Phil B is right on the money.
You'd think with it being a 73mm shell you could probably shorten the BB axle for a better chainline, but the chainstays are large and there is not a lot of clearance between the says and the rings.

Tange Prestige is still a steel frame, but a top quality one at that. Was it measured at 73mm BB width? If so, I stand corrected.

 

[PhillB]

Both my 1990 and 1991 Team Avalanches are 73mm, Measured and refitted both

 

[Black_puma]

Okay, fair enough. My 1999 GT Tequesta has a 68mm BB. I recently replaced the bb on that too, so I know from measurement that it is 68mm and took a BB from my Mongoose IBOC PRO SX which is a 1996 model with a Ritchey steel frame.

 

[PhillB]

Okay, fair enough. My 1999 GT Tequesta has a 68mm BB. I recently replaced the bb on that too, so I know from measurement that it is 68mm and took a BB from my Mongoose IBOC PRO SX which is a 1996 model with a Ritchey steel frame.

Cool, my GT Strike is 68mm, as is my old GT Talera ( I think, I’d have to double check). There was some variation between models and over time.

Wait till you start looking at GT seatpost sizing !