Giga X Pipe Bottom Bracket

Mak'em Lad;3956326 said:

Is it a simple matter to replace a TruVativ Giga X Pipe Bottom Bracket with a TruVativ Square Taper Bottom Bracket?

I know that the chainset would also need to be replaced with a square taper one.

Changing is easy enough. Is there a reason you want to make the switch?

I do not use the MTB of soft or hilly tracks, mainly on hard-pack (old railway tracks) or road and have replaced the MTB tyres for 1.9 hybrid type. The riding is easier so the small chain-set cog (22T) gets little or no use.

I also have a second set of wheels fitted with road slicks. The smaller circumference means that I now only have 10-12 effective gears. The rest are so low as to be of no use. I do not do enough roadwork to justify a second bike (or have the space to store one).

I am looking to replace the chain-set with a 50ish-40ish-30ish (from 44-32-22) one. I have seen one or two but these have a square taper.

I still trying to get my head round the bottom bracket sizes & internal/external bearing business.

Once I understand it enough I will price & source what I would need to see if it's worthwhile.

I would appreciate you input on my idea

Mak'em Lad;3956388 said:

I do not use the MTB of soft or hilly tracks, mainly on hard-pack (old railway tracks) or road and have replaced the MTB tyres for 1.9 hybrid type. The riding is easier so the small chain-set cog (22T) gets little or no use.

I also have a second set of wheels fitted with road slicks. The smaller circumference means that I now only have 10-12 effective gears. The rest are so low as to be of no use. I do not do enough roadwork to justify a second bike (or have the space to store one).

I am looking to replace the chain-set with a 50ish-40ish-30ish (from 44-32-22) one. I have seen one or two but these have a square taper.

I still trying to get my head round the bottom bracket sizes & internal/external bearing business.

Once I understand it enough I will price & source what I would need to see if it's worthwhile.

I would appreciate you input on my idea

Why don't you just buy different chainrings for your current crankset? That's a whole lot cheaper than buying a new crankset and bottom bracket.

Easier said than done, it's the Truvativ Firex chainset. That has the spindle attached to the drive side & the chainrings are non-removable. It fact the 44T ring is part of the crank.

I haven't found a chainset that has th 52-42-30 rings with attached spindle. But did see some powerspline ones but not sure if any spline will fit the Giga x pipe

As far as I can tell set up this has a 51mm chainline & uses 2 spacers (1 either side) on a 68mm shell.

I can't find any info on the length of the spindle other than shown below.

On the Sheldon Brown web site the info there says the Truvativ Firex is 113mm, ISIS spline & chainline of 48.5mm with a Q factor (whatever that is) of 168.

This seems to contradict the Boardman/Truvativ info.

How would I confirm exactly what length square taper BB I would need?

Is it posible to buy just the square taper spindle to fit the BB I have?

Thanks

You cannot replace an ISIS BB with a square taper BB.

You'll need a 113 mm J.I.S. square taper BB w/ cups that are of the proper thread for your bike. Almost all current bikes are British threaded, but some new Italian bikes are Italian threaded.