Subcompact gearing - 42-28 possible with T47 BB?

[Mark McM]

Originally Posted by donevwil

All exacerbated if riding 177.5s and 180s. I fortunately found a used set of White Industries 180s a few years ago and have now decided a second set is warranted, but with used being so scarce and both new WI and Rene Herse solutions being so expensive I'm attempting a 177.5 SRAM S900 retrofit. If any one part (crank, spider, chainrings) has to be sourced new that'll pretty much blow the financial viability. Side benefit being the reasonable Q factor of these SRAM cranks vs WI.

In your first post, you mentioned an outer chainring of 44 or 42, and inner chainring of 28. Currently on ebay there is a new SRAM X0 120/80 GXP spider and 42/28 chainrings (plus chainring bolts) for $69 (+ $7 shipping). If you've already got the cranks and BB, this is a pretty cheap way to convert to a sub-compact.

As far as the whether the big component makers will introduce sub-compact cranks, that's probably an inevitability. But they probably won't be quite the same as the these home brew setups. Any new sub-compact cranks will likely be aimed at bikes with fattish tires and disc brakes, and will likely use wider chainlines (and the accompanying wider Q factors), and not the narrow chainline (and Q factor) of road cranks.

I first started down this road for very niche usage - hillclimb road races. I was looking for a crank that had the combination of the narrow chainline/q-factor and light weight of a road crank, combined with the smaller chainrings of an MTB crank. In the search, I stumbled upon discussions of the fortunate happenstance that some brands made road cranks and MTB cranks with removable spiders which shared the spider mounting interfaces. This appears to offer the combination of features I was looking for.

[David Benson]

Originally Posted by AngryScientist

correct.

campy is still very much a traditional road racing oriented company. it is what it is.

You may yet eat your words

[charliedid]

Originally Posted by AngryScientist

there is some excellent info disseminated in this thread, linked with the one i started a few months ago here:

https://forums.thepaceline.net/showt...ht=big+waiting

Though, the lengths of the threads and the paragraphs in those threads only proves the issue - more and more people are interested in non "standard" (53/39 or 50/34) gearing these days, and these home brew solutions are cumbersome at best. scouring the internet and UK suppliers for suitable parts may be OK for us bike nerds, but too cumbersome for most people to want to bother with.

i'm reasonably certain that shimano and/or sram will see the light and offer some expanded gear ratio offerings (at the chainrings, not just the cassette) soon.

please, and thank you!

The average person walking into a bike shop in the US would have a hard time telling you how many gears their bike has. Most would shrug and ....guess.

If they do know it is because they "always ride in 2 and 6 and sometimes 5 or 7" Many never shift the chainrings...ever. "Can you just shift it into that gear you mentioned"

1X is a dream for millions of people. Countless numbers of customers when I was at the shop commented on how they wanted their bike to be 1X and then ask "how much to convert mine" They of course then just get a tune-up and say they will think about that for their next bike. That bike will come in a few years or many many more.

$400-$700 bikes should all be 1X or internal. That said, the bigger problem is the lack of time and education shops spend to make sure their customer who just bought a bike from them is versed in how to adjust it, maintain it and operate it as intended.

Bikes are impossible.

[unterhausen]

I bought a 10 speed chain and cassette for my fatbike and later my LBS told me it was 9 speed. And then we all had a good laugh at my expense. So it's not just the rubes. In their defense, I didn't tell them what bike it was going on when I bought it. I really want 1x for my wife's bike, I think it would make her a lot happier. She's not going to wear it out through over-use though.

For a lot of the riding I do, I think 2x is still best. 42/28 has worked really well on my gravel bike with the caveat that the Q is terrible and I would rather not use 175mm cranks. So being able to mix and match on road crank arms is really attractive. I think it's a bit silly to see gravel bikes with 50/34 chainrings.

[Brian Smith]

This is an interesting thread about a hillclimbing crank. I may resemble that remark.

Originally Posted by R3awak3n

I love that you don't mention campy because you know they are not going to do it.

Originally Posted by AngryScientist

correct.

campy is still very much a traditional road racing oriented company. it is what it is.

Didn't there exist a crank made to accommodate compact rings in customizable sizes? I feel certain that there was, now who made that? Could it have been Campagnolo? No, certainly not Campagnolo...
1990 called...
...they have a crank idea for you...

[NHAero]

I installed the Wolftooth Roadlink DM last night and wrapped the bars. Build is done! Components are described in Post #38 above in this thread. Test ride and big grin!
- Shimano hydros are a big improvement over Avid BB7 Road brakes - stronger braking with less effort, better modulation, and no f#%@&ing squeaking!
- The 11 speed 11-40 cassette is better than the 10 speed 11-40 I had on there as it has smaller jumps in a couple of key places
- The all-Shimano shifter, front derailleur, rear derailleur, and cassette shift better than the mixed manufacturer components I'd built up as the 10 speed, and the Roadlink does help. The R8000GS derailleur will shift the 11-40 cassette, but it shifts it better with the Roadlink.
- As Gummee assured me, it was possible to fiddle with the 10 speed CX70 and get the cage rub out of the system. I think I'm going to fool with shimming the big ring inward to make it even better. Front shifting is good - it's just a 12T difference.
- Mark McM's hack of the MTB spider and rings on the Force22 road cranks give as low of a Q factor as this frame will permit and a chainline that centers the large ring on the cassette.
- Using the 40T with the second largest cog in back gives a 30 inch low gear in the big ring so I will mostly be in the 40T.
- Bike weighs in at 24 pounds. 2 pounds could go away with a good carbon suspension-corrected fork - still looking for that White Industries unicorn :-) No carbon on the bike now except for the cranks.
- Being a 20 year old MTB, the angles are similar to a modern gravel bike, so not too slack (71.5 HA, 72.5 SA) and there's plenty of toe clearance.
- The Whisky No.7 12F bars are terrific! With the brake levers set up with minimum reach and long throw before engaging, I can brake from the drops, which I can't do comfortably with other bikes I own. 68mm reach and 115mm drop on these bars, which I learned about from Tyler in the Firefly Showcase thread.
- I'm still not ecstatic about the Delta adapter for getting the bars up high enough, but the VO Cigne stem would put them up too high.
- The pedals are Xpedo and are white, so I put a white Taupe saddle on (my current fave de jour) and against all common sense, wrapped the bars in white too.
- The bike has three uses in my mind:
* riding around MV to get places, where many routes include both trail riding and pavement - the 2.2 Contis roll well on pavement but get me through the sandy parts of the trails too
* very occasional urban riding - took it to Montreal last summer to get around for a few days, and will do the same again this summer
* rare off-Island rides with lots of dirt and steep, like D2R2. Low gear is 18 inches!

Thanks to Paceliners who helped with this, especially Mark McM.

[owly]

^ Looks like a lot of fun!

[NHAero]

Looking forward to a ride today to really check it out!
I'm grateful for the help I received here, I wouldn’t have figured it all out by myself. I know it's a oddball build with the old suspension fork, but it's perfect for here. I've been riding it as a 1x10 with mech discs, and a smaller gear range, but these changes should make it even better. I was considering a new bike, such as a Hakka MX, but I like the idea of recycling an older bike, and I'm not jonesing for a carbon bike, even though a Hakka with carbon wheels is probably 5-6 pounds lighter. If the published weight on the Unicoi is accurate (1815g) then it's almost two pounds heavier than the Hakka, but very similar to current Ti bikes like the Thunderhawk and Lynskey.

Originally Posted by owly

^ Looks like a lot of fun!

[sparky33]

Kudos on repurposing the Litespeed.

While it’s a frankenbike, every detail makes a ton of sense given where you ride...short travel in front, wide semi-slicks, drop bars for getting hi and low, etc.

Please report back on how it works out for you.

[EnginCycle]

et al,
I manufacture a spider that bolts onto a SRAM crank that allows for sub compact chainrings and corrects chainline for a 142x12 or 135x10 rear wheel. It is a 110/74BCD and uses Sugino chainrings. It will bolt onto any 3 bolt SRAM crank.

Originally I was only making them for my bicycles but I have recently stepped up my manufacturing abilities and will be selling them as a stand alone part. If you are interested feel free to message me or send me an email.

James Huang did a nice spread on one of the bicycles I made with the spider and he has some good photos included. Here is the link:

https://cyclingtips.com/2018/10/phil...lery-part-one/


Thanks for reading,
Drew

[NHAero]

That's cool!
When you say 110/74, is it designed for a 2x set-up, such that the 110 is the large ring and the 74 is the small ring? And does the large ring mount to the inner or outer face of the spider?

Photos please!

Originally Posted by EnginCycle

et al,
I manufacture a spider that bolts onto a SRAM crank that allows for sub compact chainrings and corrects chainline for a 142x12 or 135x10 rear wheel. It is a 110/74BCD and uses Sugino chainrings. It will bolt onto any 3 bolt SRAM crank.

Originally I was only making them for my bicycles but I have recently stepped up my manufacturing abilities and will be selling them as a stand alone part. If you are interested feel free to message me or send me an email.

James Huang did a nice spread on one of the bicycles I made with the spider and he has some good photos included. Here is the link:

https://cyclingtips.com/2018/10/phil...lery-part-one/


Thanks for reading,
Drew

[EnginCycle]

Originally Posted by NHAero

Photos please!

Click on the link. The photos are very close up and detailed.

[NHAero]

Steve, I come by my penchant for Frankenbiking honestly - as an eng'g student in the first half of the 1970s I studied at the feet of Sheldon Brown.

To wit:
https://www.sheldonbrown.com/org/otb.html

After he died, I picked up the OTB from Harriet Fell, his wife. I hadn't seen it in thirty years or so. When we met, it was his road bike. You can see how he Frankenbiked it!

And then there was the Thorn:
https://www.sheldonbrown.com/org/thorn-index.html

Originally Posted by sparky33

Kudos on repurposing the Litespeed.

While it’s a frankenbike, every detail makes a ton of sense given where you ride...short travel in front, wide semi-slicks, drop bars for getting hi and low, etc.

Please report back on how it works out for you.

[Mark McM]

Originally Posted by NHAero

That's cool!
When you say 110/74, is it designed for a 2x set-up, such that the 110 is the large ring and the 74 is the small ring? And does the large ring mount to the inner or outer face of the spider?

From what I can tell from the photos, it appears that these spiders are designed to use Sugino's OX series Compact+ chainrings. If so, then the direct answer to your question is that both chainrings mount to the inner face of the spider, just like the middle and inner chainrings of a 110/74 triple. The outer chainring of Sugino's OX chainrings are similar to a 110/74 middle chainring. You could use an ordinary 110/74 middle chainring as an outer chainring on this spider, but 110/74 middle chainrings are typically only available in smaller sizes (34 - 38 teeth), so Sugino makes their OX chainrings in larger sizes (up to 52 teeth), and have added anti-chain-jam pins.

I had seen photos of the Engin spider before and was very interested in it, but I had heard that they were only available on complete bikes. If they are now available separately, I'll definitely be in line to get one.

[NHAero]

Mark, how special are these Sugino chainrings? Peter White's site shows TA Zephyr rings that are 110 BCD for the middle position of a triple, from 34T to 46T, in one tooth increments at that.

Originally Posted by Mark McM

From what I can tell from the photos, it appears that these spiders are designed to use Sugino's OX series Compact+ chainrings. If so, then the direct answer to your question is that both chainrings mount to the inner face of the spider, just like the middle and inner chainrings of a 110/74 triple. The outer chainring of Sugino's OX chainrings are similar to a 110/74 middle chainring. You could use an ordinary 110/74 middle chainring as an outer chainring on this spider, but 110/74 middle chainrings are typically only available in smaller sizes (34 - 38 teeth), so Sugino makes their OX chainrings in larger sizes (up to 52 teeth), and have added anti-chain-jam pins.

I had seen photos of the Engin spider before and was very interested in it, but I had heard that they were only available on complete bikes. If they are now available separately, I'll definitely be in line to get one.