Tuesday, April 09, 2024

Damage Control

 My recent review on Shelter Tape got me to thinking about "damage control" and what parts on my gravel bikes are really the parts that are getting biffed and nicked up. 

Is it really the frame, specifically the down tube, or is it really something else? I think I know the answer, at least for me, at any rate. Upon reflection, I think I may have made a bit of a mistake with my recent Shelter Tape installation. 

You see, in my experience, the worst damage has been to my crank arm ends. Specifically the side that faces forward on the down stroke. The front wheel tends to kick up loose gravel, and for whatever reason, I find that crank arm ends take the brunt of the rocks that do get thrown up by the wheel. 

Not the down tube. Not the bottom bracket shell. Nope. It is almost always the crank arm ends, and I find that sort of amazing. Think about it. How often are those crank arm ends in a position to get hit? Once every crank revolution per side, right? I mean, the down tube and bottom bracket shell are always there. But in my experience, those frame bits almost never get biffed. 

The end of my GRX crank .

The GRX limited crank arm

I have one carbon crank arm set on the new King Fabrications Honeman Flyer. That crank set was on the Twin Six Standard Rando v2 for a while, and it is by far, the most damaged crank arm set. The aluminum ones fare better, but still get defaced and scratched. 

Crank arm armor. (Image courtesy of Jenson USA)

You can actually buy crank arm "armor", which usually describes end protectors you slip over the ends of your crank arms and are held by friction, like a grip on a handlebar, and are captured by your pedal spindle.  

I find that most gravel riders don't use these. At least, I don't see this often. If you are a gravel rider and use something like this, let me know in the comments. 

I think I may have to invest in a few sets of these things. It is obviously too late for my SRAM carbon cranks, but for some of my other bikes it might prove to be a useful addition to the bike for future protection. 

I did use something like these crank arm armor ends on the cranks of my first Standard Rando. Those were from Zefal, and apparently those are still available too. Many of these can be had in different colors as well, which could be of interest if you want a pop of color on your crank arm ends. 

The trouble is that most, if not all of these crank arm protectors are for mountain bikes. I'd like to see something made specific to GRX, or SRAM Rival, like I have. That would be good for gravel riders to have that choice. Come to think of it, maybe that is why I don't see gravel riders using crank arm end protectors.


fasteddy said...

I use the Zefal protectors on a couple of bikes. Although, they are alloy Shimano cranks, not carbon. They work and I’ll probably continue to do it as I’m apparently hard on crank ends.

tntmoriv said...

GT, I buy a foot or two of 3M “Clear Bra” or a similar wrap bulk from an auto detailer that does pinstripes and window tint. The clear bra is just as you describe with the adhesive on one side and a protective removable layer on the other, and it comes in 12 inch wide rolls. It is also nearly invisible when applied. They have always been happy to sell me as much as I need for about $5 a foot, and two feet is an almost a lifetime supply! I trim to fit, and do all kinds of areas for cable rub, chain slap, or where my bikes lean agains racks when I lock it up. YMMV.

Guitar Ted said...

@tntmoriv - Thanks for the tip! I'll have to look into that product.

Fear rothar said...

SRAM's own crank protectors fit perfectly on their road/gravel cranks, with one caveat. That is, you need to shave away the inner part of the protector on the right-hand/drive crank, at the outer edge, so that it doesn't catch the chain when you're pedalling on bumpy terrain in the smallest sprocket. Otherwise, you can unship your chain (1x) or destroy your front mech (2x).

You can also use the SRAM crank protectors on 800-series GRX cranks (and perhaps on 600-series cranks too, but I haven't tried). They fit on left-hand cranks without modification, but the pedal thread hole on the right-hand crank is in a slightly different location than they expect. The right-hand one also needs the same trimming, as I mentioned for SRAM cranks, to avoid catching the chain.

Guitar Ted said...

@Fear rothar - Excellent feedback and tips! Thank you!