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Old 04-06-14, 11:17 AM   #1
amazer98
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Salsa vaya- Moving from a road crankset to a mountain one

So I've been riding my Salsa Vaya 2 for the last year and basically like it a lot. My only issue is that I find the Apex road group too highly geared for the bike. The 48-34 chainrings are just too big for a bike with 700c X 40 rubber, at least for this 60 year old geezer.

My local bike mechanic suggested swapping out my crankset for a SRAM X05 mountain double crank with 42-28 chainrings. This would bring my gear inch spread down from something like 118-29 to 105-24. He installed the new crankset and, sure enough, the new gear range is great. My only sacrifice is that I spin out at 35 or 36mph instead of 42, which is a complete non-issue for me.

However, my front derailleur shifting has gone to hell. The derailleur no longer has enough 'throw' to put the chain on the big ring unless the chain is already on one of the smaller 3 cogs in the back. Now my mechanic tells me that what we need to do is install a mountain front derailleur, which will presumably have more range.

But I have to wonder if my Apex road brifters will correctly mate with the mountain derailleur (I know the mechanic plans to use a SRAM derailleur... maybe an X05 or X07). Is the cable 'throw' of the Apex shifters enough to actuate the mountain derailleurs so they'll work OK?

If any of you experienced gearheads have any insight into this issue, please let me know. My mechanic has been quite helpful and knowledgable in the past, but I'm getting the feeling he's pedalling into unfamiliar terrain at the moment!

Thanks!
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Old 04-06-14, 01:04 PM   #2
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may or may not, opinions differ .. as evidenced in many prior postings , [not mine] herein.

throw? is the whole chainline too far out ? my touring rigs havve been triples and those
the granny gear is right over the edge of the fixed cup


compact MTB chainrings are 42 and 44t , the arc of the outer FD cage is made to match


whether the cable pull clicks with the shifts on your left hand is a separate issue.

I suppose the local shop guys are mountain bikers , skewing their suggestion how do they set up their bikes with that crankset?

Last edited by fietsbob; 04-06-14 at 01:14 PM.
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Old 04-06-14, 01:19 PM   #3
Simon Cowbell
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I converted my Vaya to an X7 28/42 and only had to move the stock FD down a little to get it to shift well. When I put an 11/36T cassette on the back I thought I might have to replace the FD, but the Apex still works, so I'm still running it.
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Old 04-06-14, 01:59 PM   #4
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What happened to your chainline at the crank when you switched cranksets? Does your Bottom Bracket allow you to change spindle lengths?
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Old 04-06-14, 02:33 PM   #5
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Quote:
Originally Posted by Bezalel View Post
What happened to your chainline at the crank when you switched cranksets? Does your Bottom Bracket allow you to change spindle lengths?
+1

Measure your chainline from the center of the center of the downtube to the center of the distance between chainwheels. If it is greater than 45-46 mm that is probably the problem. A Mtn front derailleur will not likely work with your stock shifters. Mountain cranks are generally set up to run on a 50 mm chainline, out of the range of most road FD's.

Hint: Using a calipers, measure the diameter of your downtube and then divide in half. Add this to the the distance from the center of the chainrings to the outer edge of your downtube to find chainline. A lot easier than trying to estimate the center of you down tube when taking the measurement.

Newer cranks have less options for bottom bracket length options.

Last edited by Doug64; 04-06-14 at 02:43 PM.
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Old 04-06-14, 03:44 PM   #6
amazer98
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Just got back from the shop. Everything is perfect now; the mechanic shifted the chainrings a couple of millimeters inboard by moving some spacers that were between the pedal and the BB. I took it for a short ride and the shifts in front are right where they should be.

The move to smaller chainrings makes the bike much more comfortable. Riding on the flats with the big ring up front now puts me in cog 5 or 6 instead of 3 (counting from biggest to smallest), plus I have a couple of handy extra low gears.
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Old 04-06-14, 03:53 PM   #7
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What happened to your chainline at the crank when you switched cranksets? Does your Bottom Bracket allow you to change spindle lengths?

I think the chain line is fine. The mountain cranks have a greater Q-factor, about a centimeter wider on each side. That's fine with me, I was using KneeSaver pedal extenders anyway. I removed them and will ride without the extenders for awhile and see how that goes.

The reason I say the chain line is fine is that I think the chainrings are now located in the same plane as my old Apex. If it were much different my front derailleur still wouldn't work correctly, right? Anyway, every shift seems ok now, so I've decided to fret no more!

appreciate everybody's help- thanks!
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