Crank choices for smaller chainrings?

[Mark McM]

Originally Posted by mistermo

Two more options maybe not previously mentioned:

1) IRD Lobo cranks with versatile chainring sized like a WI VBC. And similarly, comes in black and silver:
http://store.interlocracing.com/loacr.html

The IRD Lobo cranks look promising. Does anyone know what the Q factor for these cranks is?

Also, the description says that it uses a 24mm axle, and comes with BB cups for 68/73 english cups - can anyone confirm that is can also be used with pressed in cubs for 24mm axles (assuming the appropriate spacers, of course)?

Originally Posted by mistermo

2) Dimension 110, square taper, and you can select your own rings. This is good for those who don't want to be tied into a manufacture's ring ecosystem. Could even go with Rotor 46-30 elliptical rings, if desired.

https://dimensionbikeproducts.com/pr...ets/cyclocross

The downside of the Dimensions cranks is that they are actually standard triple cranks. You can run them as 110mm/74mm double crank by removing the outer chainring, but then you'll have to use a longer BB spindle to restore the proper chainline. The longer spindle will take the already wide Q factor of a triple chainring and make it wider (and my legs prefer a narrow Q factor).

[Mark McM]

Originally Posted by BikeNY

And to answer others questions, I really hate the look of a crankset with 2 chainrings on 2 different BCDs, just doesn't look right to me.

You may not be fond of the look, but that's the way cranks are going today - and with good reason. Back in the old days (before indexed shifting and ramps and pins on chainrings), front derailleurs could only handle a moderate size difference between chainring sizes, and using the same BCD for both chainrings worked fine. But with modern wide range double crank gearing, there is often a large difference in chainring sizes (I've got a 52/36 on one bike, and a 52/34 on another). Cranks with vastly different sized chainrings can give better shifting performance if the BCD supporting each chainring better matches the size of the size of the chainring.

Not to mention these cranks have the greater practicality of being able to use the same crank for both compact and standard sized chainrings, which is benefit to both the manufacturers and the consumers. While many people think I'm a bike curmudgeon, this is modern trend which is clearly an improvement.

[Bostic]

From the IRD site:

Chainring bolts included Weight (including BB and 46-30t rings): 995g

Is that a competitive weight for alloy versus what other brands offer? I'm looking around at options now, still leaning towards a Praxis since I've been very happy with the Zayante/Turn that came with my Venge.

[mistermo]

Originally Posted by Mark McM

The downside of the Dimensions cranks is that they are actually standard triple cranks. You can run them as 110mm/74mm double crank by removing the outer chainring, but then you'll have to use a longer BB spindle to restore the proper chainline. The longer spindle will take the already wide Q factor of a triple chainring and make it wider (and my legs prefer a narrow Q factor).

I have a setup similar to this with a couple older sets of Ritchey Logic (Sugino) cranks. For drive side A, I have 46-30 rings and the 46 in the middle spot. For drive side B, I have a single, 42 ring in the middle spot, with an outer chainguard. I can swap depending on whether I want to use as touring, or commuting 1x. I'd have to check, but believe the BB is 111.5mm (JIS) and the chainline works perfectly for both swaps. Compared to other bikes, I don't notice any difference in Q Factor.

[fa63]

Originally Posted by Mark McM

The downside of the Dimensions cranks is that they are actually standard triple cranks. You can run them as 110mm/74mm double crank by removing the outer chainring, but then you'll have to use a longer BB spindle to restore the proper chainline. The longer spindle will take the already wide Q factor of a triple chainring and make it wider (and my legs prefer a narrow Q factor).

Are you sure about this? The website describes it as a double crankset for cyclocross. Also, they recommended a 108mm wide spindle for the bottom bracket (which is fairly standard for double cranksets).

[Mark McM]

Originally Posted by fa63

Are you sure about this? The website describes it as a double crankset for cyclocross. Also, they recommended a 108mm wide spindle for the bottom bracket (which is fairly standard for double cranksets).

I think the specs. might be off in the description. The photo clearly shows mounting positions for both inner and outer chainrings on 110 mm BCD arms (110/74 double cranks typically don't mount chainrings to the outer position). In the past many cranks (including some from Dimension) originally designed as 110/74 triples have been manufactured as 110 mm doubles by not including 74 mm mounting holes. When using a 110/74 triple as a 110 double, a 108 mm BB would be appropriate. I'm pretty sure this cranks is mislabeled as a 110/74 cranks, and instead this crank is intended to be used only as a 110 mm double (which means a minimum chainring size of 34 teeth). This would be consistent with typical cyclocross usage.

[Mark McM]

Originally Posted by mistermo

I have a setup similar to this with a couple older sets of Ritchey Logic (Sugino) cranks. For drive side A, I have 46-30 rings and the 46 in the middle spot. For drive side B, I have a single, 42 ring in the middle spot, with an outer chainguard. I can swap depending on whether I want to use as touring, or commuting 1x. I'd have to check, but believe the BB is 111.5mm (JIS) and the chainline works perfectly for both swaps. Compared to other bikes, I don't notice any difference in Q Factor.

Older Ritchey 94/58 and 110/74 cranks had low Q factor for triples. I was using an older 110/74 as a double crank with a 108 mm BB, and it was just fine. After it cracked, I replaced it with a Dimension 110/74 (also used as a double), and the Dimension crank had a much wider Q factor (even on the 108 mm BB). I could never get used to the wider Q, and only used the Dimension until I could find another Ritchey 110 crank.

[fa63]

I see. Well, let's hope the description is correct; I already ordered the crank arms, a 110 BCD 46-tooth big chainring and 74 BCD 30-tooth small chainring, and a 107 mm Shimano square taper BB. Would be nice if it worked

Originally Posted by Mark McM

I think the specs. might be off in the description. The photo clearly shows mounting positions for both inner and outer chainrings on 110 mm BCD arms (110/74 double cranks typically don't mount chainrings to the outer position). In the past many cranks (including some from Dimension) originally designed as 110/74 triples have been manufactured as 110 mm doubles by not including 74 mm mounting holes. When using a 110/74 triple as a 110 double, a 108 mm BB would be appropriate. I'm pretty sure this cranks is mislabeled as a 110/74 cranks, and instead this crank is intended to be used only as a 110 mm double (which means a minimum chainring size of 34 teeth). This would be consistent with typical cyclocross usage.

[zzy]

It's already been said, but I really wish more companies made 110BCD big rings for the middle position on a triple. Sugino does for the 601 subcompacts. I was actually wondering if I could countersink my own rings to make it work, along with a 74BCD 30t ring.

[mistermo]

Originally Posted by fa63

I see. Well, let's hope the description is correct; I already ordered the crank arms, a 110 BCD 46-tooth big chainring and 74 BCD 30-tooth small chainring, and a 107 mm Shimano square taper BB. Would be nice if it worked

+1. I've ordered one too. After getting bike set up, I'll compare to the aforementioned Ritchey cranks.

[BikeNY]

Originally Posted by Mark McM

I think the specs. might be off in the description. The photo clearly shows mounting positions for both inner and outer chainrings on 110 mm BCD arms (110/74 double cranks typically don't mount chainrings to the outer position). In the past many cranks (including some from Dimension) originally designed as 110/74 triples have been manufactured as 110 mm doubles by not including 74 mm mounting holes. When using a 110/74 triple as a 110 double, a 108 mm BB would be appropriate. I'm pretty sure this cranks is mislabeled as a 110/74 cranks, and instead this crank is intended to be used only as a 110 mm double (which means a minimum chainring size of 34 teeth). This would be consistent with typical cyclocross usage.

You are correct, that cranks can run 2 110 BCD chainrings. The picture posted clearly shows mounting tabs for 74mm chainrings also though. I think they just took a triple 110/74 crank and relabeled it a double.

[oldpotatoe]

Originally Posted by zzy

It's already been said, but I really wish more companies made 110BCD big rings for the middle position on a triple. Sugino does for the 601 subcompacts. I was actually wondering if I could countersink my own rings to make it work, along with a 74BCD 30t ring.

TA makes a variety of rings in 110mm BCD, including 'big rings'. Just use short/track CR bolts.

[fa63]

I am a bit ignorant when it comes to triples; does this mean that if I were to run a 46-tooth 110 BCD chainring as the big ring and a 30-tooth 74 BCD chainring as the small ring, I would need to install a bash guard or something to take up the space of the third chainring?

Originally Posted by BikeNY

You are correct, that cranks can run 2 110 BCD chainrings. The picture posted clearly shows mounting tabs for 74mm chainrings also though. I think they just took a triple 110/74 crank and relabeled it a double.

[oldpotatoe]

Originally Posted by fa63

I am a bit ignorant when it comes to triples; does this mean that if I were to run a 46-tooth 110 BCD chainring as the big ring and a 30-tooth 74 BCD chainring as the small ring, I would need to install a bash guard or something to take up the space of the third chainring?

No, just use these, mount CR on middle position. Short chainring bolts, for single rings, used in track also. Done this bunches of times for shimano and Campag triples..

[fa63]

Great, thanks!