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Double chainrings and bashguard

Submitted by l'autre_Paul on Apr 4 2011 8:43pm

I wondered if anyone had come up with a good solution for the need to wear two chainrings AND a bash guard. I run two sets of gearing, one for getting there, one for playing there (38/16 and 32/22, keeps the chain the same length). But it does mean I perpetrate the great evil of an exposed chainring in pick ups. Granny rings on triple cranks tend to be too small (30T being the biggest I have found) so using that option seems out of the question. It struck me recently that maybe a bash guard could be fitted with chainring spacers to the outside of the big ring. Any one done this? Any problems?

#1
I like gum's picture
I like gum
Seattle

confused with the post. are you asking if there is a bashguard that works on top of a double chainring ? you could grind the third chainring down and turn it into a makeshift bashguard. file off all of the teeth off...or... wrap a chain around the third sprocket and that could be considered a bashguard.

side thought: if you can't find a bigger granny gear, then consider a different crankset.

Apr 4 2011 11:45pm
#2
hurricanejosh's picture
hurricanejosh
Edmonton Bike Polo

he doesn't want to use the tiny bcd inner ring on a triple. not only are the tooth sizes really small, but you can't get very good quality chainrings for an inner because you aren't meant to ride on them much. he's asking if there is a way to fit two standard BCD chainrings, and a bashguard.

there is a premanufactured solution for this, but it is designed for a 44 tooth outer. maybe they would do i smaller one custom? i'm assuming it's just CNC
https://www.purelycustom.com/c-71-3x1-armor-bash-guard.aspx

i think sandwiching spacers between your outer ring and a bashguard could work ok, as long as you can find long enough chainring bolts. i wonder if anyone is running a milwaukee polo guard as an outer with an alternative inner? but 35 is probably smaller than you want outer. i'm guessing 104 or 110 BCD would be the options for this setup

Apr 5 2011 12:53am
#3
l'autre_Paul's picture
l'autre_Paul
Montreal Bike Polo

Hi Josh, yes, what you said, I want to know if anyone has run two chainrings with the bash guard attached to the outer ring with spacers. I do like the MKE polo guard but 35T is too large for me for polo, and too small for me for the road. The purely custom one you posted looked ok if a bit big (38T or 36T is what I'd like), but I think there's a solution in here.

I did find a lovely set of 165 cranks with a granny ring BCD of 74 which fits a 30T, but discovered it's for a skinny ass road bike, not the weird fat ass early model Pompino I have.

Knowledge by experience, such as things like outer ring BCD and corresponding granny ring BCD for various cranksets (and oddball solutions,) is the glory of the LoBP.

Apr 5 2011 11:15am
#4
bradq's picture
bradq

This is absolutely possible, and is the way that people would run triple mountain cranks and bashguards way back when.

Any older or well stocked shop should have chainring bolt spacers, and there are extra long chainring bolts out there. Two rings and a guard spaced to the outside should work just fine for you assuming you can get your chainline correct. You may have to cut or grind the guard to fit around the crankarm as it will be more apt to interfere with it spaced to the outside.

Apr 5 2011 12:08pm
#5
scottles's picture
scottles
Melbourne

x2. I'v been running a setup like this for the last 18 months with no issues. There was a bit of extra filing to get the guard to squeeze in under the crank arm with my new cranks (shimano R600), but worked fine unmodified with my old Sugino GT cranks.

Apr 10 2011 5:08pm
#6
Zack's picture
Zack
DC Bike Polo

The Blackspire Big Ring protectors are designed for this. polycarbonate or aluminum. Not sure if they fit your chainrings sizes.

Apr 6 2011 4:30pm
#7
l'autre_Paul's picture
l'autre_Paul
Montreal Bike Polo

Those are massive. And local too. Although their SuperGods come in 38T, which as Bradq suggests, I could stack out from the outer ring anyway. Cheaper and maybe less grinding to fit behind the crank. Many thanks for your opinions.

Apr 6 2011 8:20pm
#8
timtim's picture
timtim
Portland Bike Polo

check out this guys stuff, bbgbashguard.com. he is local here in portland and does stuff at a lot of the cyclecross events. I bought one from him and was running it for a little while, but I got one with a lot of cutouts in it instead of one of the solid ones and it got bent up pretty bad in a gnarly crash. his stuff is pretty reasonably priced and he is a pretty nice dude to boot.

Yo Dawg I heard you like redundancies so we got a PIN number for your PIN

Apr 11 2011 2:12pm