Steamroller Chainline
 

I am new here and, while browsing around the forum, have notice discussion on the chainline on the steamroller complete build. I bought my bike late spring/early summer in 2007 but am not certain it is a 2007 model. I have also seen it mentioned that the 2008 models have resolved the issues.

My primary inquiry is whether the issue is model specific-- I may have bought a 2006 model in 2007-- and whether there is a good way to verify the year of the model?

I hope this issue isn't over discussed and would appreciate insight.

The crank is what is in question. Does your bike have this crank?

http://www.benscycle.net/images/large/SuginoRD_LRG.jpg


If so your chainline is probably 1mm off becuase RDs can only really get a 43mm chainline, while your hub is ~42mm.

The argument was mostly over why Surly would release a complete bike with this issue, but lots of people run these cranks without any issues on all kinds of bikes.

My bike came with RD2s, which are the model with a 45 mm chainline according to other discussions. I do occasionally notice noise when the chain is dirty but one symptom I have is that the chain will shake/vibrate at about two point every rotation of the cranks at slow to moderate speed. I notice this when I have the bike upside down. For instance if I spin the rear wheel to verify it is aligned after changing a tube. It always bugged me but I just want to verify it is not a safety concern. I ride a front brake but still feel that a broken or thrown chain could result in some cranial damage.

Since this thread got buried is it safe to assume there is no safety issue?

i have the 08 model steamroller and the chainline seems right on...there is noise for me because i am running a 1/8 chain on a 3/32 cog

i have the sugino rds on mine too

I agree that mine looks on to my--admittedly untrained--eyes but I had read discussion about a ~3mm deviation in various threads. My worry is that I threw a chain once soon after I first started riding fixed, since I was not maintaining the chain tension, when going down a sizable hill and I would not like to relive the experience.

The noise from a chainline discrepancy is not my concern as much as the safety/mechanics of it.

keep that tension tight, i check mine once a week or so or when i have been skidding or climbing some larger hills...i never want to throw a chain so i make sure it is always in line and tensioned properly

After the mishap I decided to get one of the surly tensioner, which get mixed reviews on here, and it seems to keep it tight. I could have saved the cash and just been more vigilant but sometimes I get lax in maintaining my bike.

Thanks for the response. I'm gonna conclude that it isn't an (major) issue and not obsess over it until I have the income to upgrade to the 75's I dream of.

ah yes the 75s...i found some great tensioners through benscycle that i am going to pick up soon, i like them because they are smaller and you can adjust them using an allen wrench...they should fit the surly track ends...
http://www.benscycle.net/bmz_cache/3...ge.150x112.jpg

I find they are a great investment. The ones pictured have a better look then the surly's and no matter what you use I believe you'll like it. I only run one and you probably wouldn't need two unless you think it gives a cleaner look (or you are a beast).

Here's the skinny:

All steamroller completes (i.e., the stock Surly steamroller built by Surly and regularly bought at your LBS) come w/ Sugino RD cranks. The chainring on these cranks (normally) sit 45mm away from the middle of the seat bar on your frame, thus giving a 45mm chainline. The Surly cogs which come stock on the complete Steamrollers are speced to work with a chairing that gives a 42.5-43.5 mm chainline.

BUT this is nothing to worry about because the Steamroller also comes with a 3/32 8-speed chain, a chain that can easily handle this deviation in chainline with no danger in the chain coming off, little to no extra wear on the cog and chainring, and little to no noise elevation (bc 3/32 chains just run quieter than the 1/8 chain on your standard track bike; and most of the noise comes from either having the chain too tight or just having noisy cogs, and Surly cogs can be noisy).

Chain tensioners are not necessary unless you are heavy or unless you have an extraordinarily strong pedal stroke.

Not to highjack this thread, but what about Sugino RD's on other bikes with, say, a Soma cog & Surly lockring? Did Surly take the 45 mm chainline into account when including it as the stock crankset, & create a cog that would minimize the chainline differential? Can a Soma cog work in the same way, or am I resigned to placing the chainring on the inside of the spider?

straight chain
 

Why can't the wheel bearing races be moved the 1mm or so in the right direction and the spokes adjusted slightly? I set up my own single speed, actually a two speed but yea.....its not fixed. I suppose that's one good reason for a freewheel. I assume the Surly bike has loose bearings and adjustable races of course. :innocent:

some days i feel like a beast...i weigh 210 or so
seems skidding and climbing hills pulls the wheel forward in the track ends...wouldn't hurt to get a tensioner

meh

My pedal stroke likely isn't out of the ordinary but I am very heavy for a cyclist and would often find the chain got loose.

Also, in reference to your other reply, you talked about the 3/32 chain but I hand switched up my rear wheel for a new one and used the rear wheel's flop flop side, and all of the drivetrain (i.e. cranks, chainring, chain), when making a SS for a friend. The wheel was used but in good condition and also has a surly hub. I bought another set of RD2s thinking it is best to keep all variables equal but I got a new 1/8 chain ring and chain because the cog on the wheel I bought was 1/8.

So I am running essentially the same specs as stock but with a 1/8 chain and am concerned about the lach of flex in the 1/8 chain.

It seems just to be pragmatic in this case: if the chain does not slip off, or if it does not seem like it is going to slip off (of course, while keeping the chailine reasonably maintenanced) then there should be no problem. Just look and judge for yourself. You may lose some efficiency in this set up, but it is probably not enough to really make a noticeable difference in performance.