Bicycle Mechanics - Crank set

Okay, having completely missed the little fact that the Deore Chainset is 9sp only and not having the cash to replace shifters, wheel, cassette and chain as well as the bottom bracket and chainset I'm on the look out for a reasonable 7/8sp alternative...

My first thoughts are:

I either still go with a Deore splined BB but go up to Deore XT hollowtech (I don't think there's an 8sp LX) but this adds a bit to the price.

or

Go for a UN72 BB with a mid-level Nexave chainset giving me 48-38-28.

or

Go for an Alvio chainset with 44-32-22 and a UN72

Is the XT option likely to be worth the extra 30% over Nexave, 50%? over Alvio?

As I largely do road work, with a little off-road would the bigger gears of Nexave be better?

Any thoughts appreciated.

Richard

I would go for the higher gears for road use. They are still low enough for off road.

Just found mention of Nexave in 8sp compact hollowtech option.

I know a 28 would be low enough for my needs, but are 48 cogs too big for off-road (I mean physically too big, rather than too hard to push if you see what I mean...).

Any experiences of Nexave? There seems to be a paucity of reviews on the web?

Richard

I strongly prefer and recommend the traditional 110/74mm BCD, which can take you down to 24T, if necessary. I have used a 48-40-24 Sugino triple on my mountain bike for several years, with no clearance problems, and with my seven-speed 13-26 freewheel, I get a 4:1 range of ratios, from 24 to 96 gear-inches.

A strong word of caution on the UN-72: I have been unable to make either a White [by Sugino] or a Shimano RSX crank seat fully (and what I consider properly, based on years of experience with cotterless cranks) onto a UN-72 spindle. You may need a shorter spindle than you think, and I am still very uncomfortable with having the spindle seat only 1/2 to 2/3 of the way into the crank. I bought what should have been the correct-length UN-72 for my son's bike (68mm BB shell) and ended using it on an aluminum frame with a 73mm BB shell. Interestingly, Sheldon is starting to compile a database on crank-spindle compatibility issues.

Thanks for the advice - the lbs is ordering the Nexave non-compact chainset, I think as I use the road more than I ride off-road the larger set will out-weigh any advantage the hollowtech weight saving would have given me. XT was just a little too dear and didn't have the larger cogs - quality wise the lbs reckoned durability was about the same across the cranks I was looking at, with weight and cog size being the deciding features. They'll also be 175mm rather than the 170mm I have been using, which will hopefully be better for my 6ft height.

I'm going for the UN72, and relying on the lbs to get the right spindle length. I did think about getting the parts and fitting them myself, but they're not going to charge me labour so I decided it wasn't worth buying the tools this time.

Richard

Just as an update:

The shop fitted the Crankset/Chainset on Thursday so I've put it through 50 plus miles now.

The cranks are hollowtech so are fairly light, it shifts very smoothly compared to the old Suntour set. I don't know how much difference the 175mm cranks over 170mm make but on the hills I'd say there is almost half a gears worth of improvement over the previous set up.

I can't comment on longevity yet, but first impressions are good, and seems a reasonable alternative to Deore if you're running 7 or 8 spd, and as I use my MTB as an on-road commuter more than go off-road the 48T top chainwheel is nice to have. Mine's in the T400 series, and I think they do a 44T version as well. I don't know about the lower T300 series.

Richard

Originally posted by Richard D
Just as an update:

The shop fitted the Crankset/Chainset on Thursday so I've put it through 50 plus miles now.

The cranks are hollowtech so are fairly light, it shifts very smoothly compared to the old Suntour set.

Did the Hollotech cranks seat properly onto the UN-72 spindles, or only halfway?

Originally posted by John E


Did the Hollotech cranks seat properly onto the UN-72 spindles, or only halfway?

I ended up with a UN-52 (the set needed 118mm spindle and the longest the shop had in UN-72 was 113mm). The shop fitted the cranks so I can't really comment on how well they fitted other than that the mechanic seemed happy enough - I didn't ask him the direct question.

Richard

John E,
Now that you mention it, I have tried older (mid 80's) 105 and RSX as well as Sugino AC 130 cranks on a UN72. I noticed that all seat farther out on it than they do on the mid 80s bb the 105 crank was originally on. The gap between bb shell and crank on the original bb was around 1/8" while on the UN72, all three cranks seat with a gap noticably wider, 3/16-1/4". They seem secure and well seated, but you are right, there is a difference. At first I thought I might have reversed the spindle, but with English threading the sealed bb can only go in one way, right?
Regards,
Raymond