IRD Sub-Compact Reviews/Info?
 

I did an internal and external search for info regarding the IRD Sub-Compact 30/46 crankset. Specifically, I'm looking to hear reviews re the quality or any "gotchas" that may have popped up after you installed it. I have two freewheel, 126mm, friction shift bikes left in the fleet; I'm looking at the IRD to get the gearing down to something manageable for the hills and the numbers seem like they'll be perfect.

From my research I know they're JIS and the recommended BB spindle length is 118mm; that seems a little long, maybe even triple territory? The bikes are an 86 Spec Allez SE and an 84 Guerciotti SL. I'm kinda stuck on the IRD for the way they look and that they come in 172.5mm unlike the Velo Orange.

So I guess my questions are:

Anybody using the IRD and how do you like it?

Was a 118mm BB spindle indeed what was needed?

Thanks

I was unaware of the IRD set. I’ve been debating whether to try the FSA crankset, also JIS. For some reason I just don’t want to go with a triple.

Ird crank
 

Don't have one but the old Stronglight 93 double uses a 118 spindle.

Stronglight 99s make a good compact for vintage bikes as well and chainrings are still available.

I have an IRD 46/30 compact as well but I haven't set mine up yet. I'm planning on using it on my 1978 Trek TX 900. I'm running mainly campy gear on that bike and like you I want some decent climbing gear. I figure with a super record RD I can run 46/30, 13-28 7 speed. I wish I could find a 12-28 though.

I have an IRD triple
 

on my 1985 Trek 720. I can't speak to the double, but my assessment of the triple (48-36-24t) is that it is a fine crankset. Also, my bike requires a 127.5mm spindle. Some bikes require only a 122.5mm, so 118 for a double doesn't sound outrageous.

I've got an IRD "defiant" crank (with some custom milling and anodize by Jon "Drillium" Williams, RIP) and I'm very happy with this part, it's excellent quality.

Mine is a 110 BCD but it looks like the same forging as the sub-compact. If I correctly recall I used a Phil 108mm spindle with a +3 mm offset.

These are really nice parts, readily available and easy to install. The Stronglight mentioned above is a good vintage item but has the limitation of a minimum 38T inner ring, requires a unique and hard to find removal tool, and is made of very soft aluminum so requires great care during installation and removal,

Mark Petry
Bainbridge Island, WA USA

https://cimg4.ibsrv.net/gimg/bikefor...14c6df393b.jpg

https://cimg7.ibsrv.net/gimg/bikefor...179bfdd4b6.jpg
Just get a mid level Shimano 110 bcd crankset and a 46t chainring from the bay and a 34 from a compact crankset and it works.

I'm not using one, but kudos on them for choosing a smaller BCD that makes a 46/30 easy. There are some pretty ridiculous contortions going on in the "gravel" world to get rings smaller than 34T onto 110mm BCD cranks.

118mm is what my old Sugino GT needs to be set up as a compact double, so it sounds right to me. Older-style cranks with straight arms tend to need longer BBs than modern ones with the arms curving inward to meet the BB spindle.

I'm stuck on the 30T small ring.

I used an IRD 50/34 compact once upon a time and liked it FWIW

The difference between 30 and 34 is 3gear inches

Bicycle gear calc

https://cimg5.ibsrv.net/gimg/bikefor...f6b847e085.jpg

Got any more info on the specific crank model? I 've seen a bunch of crank arms like that listed as BMX cranks but wasn't sure if they where set up or fully machined to take a larger outer ring.

In my experience, the difference between a 30T chainring and a 34T on a climb like Alpe d' Huez is more significant than a gear chart will reflect. I'm stuck on the the 30T as I have Mt Evans/Pike's Peak in my sights for next year.

https://cimg8.ibsrv.net/gimg/bikefor...0d28fcb84b.jpg
https://cimg0.ibsrv.net/gimg/bikefor...ec46b7384a.jpg

If the IRD doesn't work out and you want to try 2x10 there is also the new Shimano GRX 2x10 46/30 crankset with 172.5mm cranks.

You'll need a new threaded BB to make it work. About $150 for the whole package.

Perhaps not as much of a looker as the IRD, but a nice product at an affordable price.

One possible place among many to find it is:
https://www.modernbike.com/shimano-g...nterface-black

https://static.modernbike.com/256/ma...0808121136.jpg

Perfectly serviceable part. 118mm UN55 BB does the trick. Unlike most all the other sub-compacts out there it has a C&V vibe, although it isn't that much of a looker....and doesn't cost an arm and a leg doing so.

What size are you looking for, 172.5? I have a crankset and BB lying around in the parts bin I'm no longer using (175mm)

I appreciate the offer, I'm looking for a 172.5, 30/46.

I'll have to go with an Italian thread version of the 118mm x 70mm UN55 for the Guerciotti. The IRD does have the look I'm after. Is yours a 30/46?

The ird does look cool. I have an old sugino mountain crank that has the triple version of that and discovered that t.a. makes a 29 for the 94mm bcd. Pretty cool really. They also make a 33 for the 110. These are tiny differences but the placebo effect shouldnt be discounted. Not to mention the differences that are important are the percentage of change. Hence 34 to 30 may only be 3 gear inches, but its also over 10%. At least another gear on a road bike. Might be the gear you need.

Another option for building a vintage sub-compact: the SR Apex-5 Touring. Effectively a Stronglight 99 copy, but without the need for the proprietary removal tool. I just put a 50/32 on mrs non-fixie's new bike. The 86mm BCD will take a low as 28T rings.

https://cimg9.ibsrv.net/gimg/bikefor...05c99793e6.jpg

Upon further checking it is a Fuji crank on my Fuji Stratos, a Japanese market bike.
Here are the markings on the inside of the Crank arms
https://cimg5.ibsrv.net/gimg/bikefor...d60869d100.jpg
https://cimg6.ibsrv.net/gimg/bikefor...a791400ed5.jpg