Crash Test Dummy
Polymer v alloy bashguards
I put a Shimano SLX double crankset on my Stumpjumper last spring and have appreciated the extra clearance it offers over the old triple. The protection the bashguard offers has also come in handy and has encouraged me to become more aggressive in riding over trail obstacles. It has proved pretty durable over rocks and logs.
I would like to save a little weight by getting rid of the stock polymer bash and, as well, improve the appearance by getting rid of this ugly piece of plastic.
I have read, however, that alloy bashguards such as BBG (one of if not the lightest bash available) may transfer too much impact force to the mounting bolts, causing failure.
Anybody have this problem? I note one of the comments on the above article suggested replacement of the standard bolts with heavier ones but that seems counterproductive in terms of weight savings.
Steel bolts or at least Ti bolts are a good idea throughout a bike. Aluminum bash ring bolts, headset bolts, axles etc are just asking for trouble.
Some of these bashrings have a metal sleeve that further strengthens the bolt interface. BBG, aiming at being light, does not have this.
btw there are carbon fiber 'bash rings' that are near half the weight.
For what it is worth, I prefer metal bash as well, however, the poly bash do seem to last longer (unless you hit concrete a lot, i.e. urban riding)
If I go with XTR for my next cranks, I may opt for BBG, unless I can find someone still making a Ti bashring.
Regional Race Manager, Knolly Bikes
Washington, Montana, Idaho, South Africa
One of the benefits of the plastic bashguards is that they do absorb and disperse impact very well, another benefit is that they slide over rocks with less friction.
A standard BBG guard will become roughened up to the point that it doesn't slide well over obstructions, also certainly with enough impact will damage the bolts.
If you're smacking you're bashguard with a lot of force (a la downhill) then stick with the polymer guides. If you're an aggressive trail/AM rider who occasionally smacks his bashguard then go with the BBG.
I've used BBG for a while, the inner guide and the superlight are very flimsy. The standard guard is plenty strong and I've taken chunks out of the aluminum edge. Never damaged a bolt though.
"...like sex with the trail." - Boe
Bbg here too. Never damaged any bolt.. hit plenty of rocks with it