GXP is so awesome

GXP is so awesome

I love the SRAM GXP and spider system. I’ve been using it for years and it has produced a great deal of value for me. I have a trouble free bottom bracket and axle interface that works just as well in a press fit application as threaded. I can change spiders for 1x, 2x, 3x or just go direct mount. 45mm, 47.5mm, 49mm or 52mm drivelines are made possible with a small part swap instead of new cranks. There’s really no arguing that this system isn’t wonderful.

One big problem that I have with the current bicycle market is the lack of good crank choices for hybrids. For hybrids, we need a 47.5mm driveline and have a choice of 1x or 2x ring setup with as narrow a crank as possible, larger tires, and disc brakes. This is easy enough when running 1x but the addition of a front derailleur makes things very difficult.

This is a problem that was solved close to 10 years ago. SRAM issued the road Wide-Axle format. This gave us the room we needed. What happened? The ignorance of product managers, shop workers, and cross racers failed to understand the use of the format and SRAM was forced to stop importing the product. Never underestimate how little bike ‘pros’ actually understand. This was an incredible loss to folks like me that are trying to make bikes work better. Lucky for me, during that time, I had a few WA cranks that I could use but I needed more.

Somehow, I was able to procure a box of 10 SRAM Rival cranks with Wide Axles. The good news was, I had a cranks (Q156) I could use for great hybrids. The bad news was how disgusting the Rival crank arms are to look at and how heavy they are. The box sat. For a while. Recently, my new hybrid designs started the design phase. It was time to make some decisions. I took some proper measurements for what I had to work with. That started me down a wormhole….

I realized that I could try to press the axles out of the Rival WA crank arm and install them into a Force (Q153) crank arm. Simple in theory. Could it be done? It could. With just about a ton of force the axle gives way and slides out. A simple press fit. 1/2 ton going back in.

Now I have 10 more rad cranks arms to get me through until the bike industry comes to it’s senses…but I’m not holding my breath.

Here’s the skinny on GXP axles and arms:

GXP86 – Narrow-Axle road symmetrical. PF4186 or T3568, Axle from face, 107mm. For use with 1x/2x 45mm chainline or 1x 47.5mm chainline. 130/137mm hub spacing for 45.0 mm chainline, 135/142 mm hub spacing for 47.5 mm chainline. Symetrical arms.

GXP89 – Wide-Axle road symmetrical. PF4189 or T3572, Axle from face, 112mm. For use with 1x/2x 47.5mm or 1x 45mm chainline chainline. 130/137mm hub spacing for 45.0 mm chainline, 135/142 mm hub spacing for 47.5 mm chainline. Symetrical arms.

GXP92 – MTB asymmetrical. PF4192 or T3572+2.5, Axle from face, 114.5mm. For use with 1x/2x/3x 50 mm 1x 49/50 mm chainline or 1x/2x 52/53 mm chainline. 135/142 mm hub spacing for 49/50 mm chainline, 148 mm hub spacing for 52/53 mm chainline.

MTB crank arms cannot be interchanged with the narrower symmetrical systems without playing funny games with the bottom bracket shell and chainline. Be careful you understand what you are doing when attempting this.

Cryo makes things fun!!!