[crashwins]

So, following the advice of this thread, I pulled the trigger on a 22" Mob frame. I taking the parts from my Staats 1x9 and transferring them over to the Mob. It has a Profile Racing crank and a 36t front chainring going to a SRAM cassette in the rear. I think I'll need a chainguide for this. Anyone have any suggestions? I'm also told that 36t will be too big in the front and need to go down to 32t. Hoping that someone has experience setting up their Mob this way. Thanks!

 

[cmc]

So, following the advice of this thread, I pulled the trigger on a 22" Mob frame. I taking the parts from my Staats 1x9 and transferring them over to the Mob. It has a Profile Racing crank and a 36t front chainring going to a SRAM cassette in the rear. I think I'll need a chainguide for this. Anyone have any suggestions? I'm also told that 36t will be too big in the front and need to go down to 32t. Hoping that someone has experience setting up their Mob this way. Thanks!

i'm running a 30t profile sprocket with profile bmx cranks (6 inch spindle) and there is 1/8" (3.175 mm) clearance between the sprocket teeth and the frame. i don't think i could run 32t without spacing the sprocket further away from the frame which might then cause chain alignment issues. so although 32t is probably possible, i think 30t or smaller is a better choice.

 

[Paulyd]

he's running it with gears though, so wouldnt a couple of mm not be too big of a problem?

 

[crashwins]

Thanks. I've never had gears setup this way before. Just standard xc-style 1x9s. How does this bike ride with a 30t up front? Is the ratio good for 4x and whipping around town (I'm not a 4x racer, just like that kind of setup for my needs). did you need a chain guide too? Thanks!

 

[cmc]

Post your 4x/DS bikes
http://www.ridemonkey.com/forums/showthread.php?t=221740


In this thread, a dude is talking about 32t 1X9 on a blackmarket riot. He's mentioning how close the clearance is.

http://www.socaltrailriders.org/forum/general-discussion/27411-checkout-my-new-black-market-riot.html

This dude has a 33t profile bmx sprocket mixed with 1X9:

The Transition Bank 4x complete comes with 1X9 parts kit:

http://www.transitionbikes.com/Bikes_Bank.cfm

Parts Kit: Bank

Truvativ 32 (Included with crankset)
e.thirteen SRS+
Truvativ Holzfeller 40mm
Truvativ Hussefelt
Cane Creek XXCII
Truvativ Holzfeller 170mm
Truvativ Howitzer Team 73mm
Avid Elixir CR 6"
Avid Elixir CR 6"
Maxxis Crossmark 26x2.25 60a Foldable
Maxxis Larsen 26x2.0 62a Foldable
Welterweight
Transition Stepdown
Truvativ Hussefelt
Transition Park n' Ride FR
ODI Ruffian Lock-on
SRAM PG950 11-26
TBC Revolution 28
SRAM X9
N/A
SRAM X9
N/A
KMC X9.93

 

[freeridefool]

You could run a small front ring... like a 30 and then just use a road cassette in the rear.

 

[crashwins]

How do you think 32 x 16 would be? Maybe I should just run it as a SS. I already have a 1x9 for trails/xc/am stuff. I just want to ratio right where I can manual and do other fun stuff

 

[Paulyd]

32-16 is a fairly easy ratio, especially for 4x.

 

[cmc]

How do you think 32 x 16 would be? Maybe I should just run it as a SS. I already have a 1x9 for trails/xc/am stuff. I just want to ratio right where I can manual and do other fun stuff

32 / 16 is too spinny. the only people who recommend a 2:1 ratio are xc single speed riders who are used to sit-and-spin climbs. bmx'ers are used to using momentum and standing and mashing to get up hills.

the formula is:
Front Sprocket / Rear Sprocket X Wheel Diameter = Gear Inches

55 gear inches is the classic BMX gear inch rollout. You can go slightly spinnier or stouter depending on your preference, but 55 should be considered the medium "all around" gear.

So, for example

44 / 16 X 20 = 55

25 / 9 X 20 = 55.55


these are all good choices for 26":

30 / 14 X 26 = 55.7
28 / 13 X 26 = 56
26 / 12 X 26 = 56.3

i'd say with a MOB, SS is the way to go, unless you have a really good reason for needing to shift.

 

[crashwins]

Thanks - that's very good advice. I appreciate it. Well, I spent years on a Bianchi SS MTB out in SF. I loved it, but wanted something more flickable, where I could manual easy, etc. It was a 32x16. I know the Mob is more a BMX than anything, but I got a good deal on a frame and thought I could get something where I could actual commute (really just ride a few miles comfortably) and drop the seat for "play." I'm not a park king or anything and don't pretend to be, just someone who loves to ride and wants something a lot more dynamic. That's why I was thinking gears I guess. My thoughts on 32x16 were that I could bring up the seat and ride, and then drop it and have enough spin to screw around on the street. That ratio would also make hills more comfortable -- a lot where I am.

 

[cmc]

Thanks - that's very good advice. I appreciate it. Well, I spent years on a Bianchi SS MTB out in SF. I loved it, but wanted something more flickable, where I could manual easy, etc. It was a 32x16. I know the Mob is more a BMX than anything, but I got a good deal on a frame and thought I could get something where I could actual commute (really just ride a few miles comfortably) and drop the seat for "play." I'm not a park king or anything and don't pretend to be, just someone who loves to ride and wants something a lot more dynamic. That's why I was thinking gears I guess. My thoughts on 32x16 were that I could bring up the seat and ride, and then drop it and have enough spin to screw around on the street. That ratio would also make hills more comfortable -- a lot where I am.

legendary hills of SF

 

[crashwins]

Horizontal dropouts. But I have the adapter, which should accommodate the skewer.

 

[cmc]

uphill BMX in SF:

downhill BMX in SF:

 

[crashwins]

Ha, I was a messenger there. I remember what those hills felt like. The "wiggle" was for the weak