A few weeks ago I picked up a Speed Concept 7.8 that has a 46/36 crank set. I’m not sure how I feel it, on the trainer where I spend 99% of my time it is works out pretty well but I’m not so sure about a hillier course like IM Louisville which I’m doing later this year. I come from a 52/36 and a 50/34 of which I preferred the 50/34. I’m a little worried I may run out of options on the steep hills. Can anyone offer a yah or nah on the 46/36? My cassette is 11-26.
A 46 seems like something that would be used in a 1x setup. That seems odd to me, but there could be a good use case for it I guess. I’d get it replaced with a 52 or 50 personally.
46x36 is usually used on cyclocross bikes.
I run a 46/36 with an 11-32 on my gravel bike. The low gear of 36/32 is nice to have on a muddy or icy hill in New England, however I am often let down by the 46/11 combo on fast gravel down hills. When I use it as my commuter/rain bike on pavement, I notice this lack of high end even more. I suspect on your go-fast tri bike you will not be very satisfied. For a reference, I run a 50/34 with an 11-28 on my road bike and really like the setup for pavement. Enough top end to spin until I must tuck and enough low end to get up even the steepest hills. 46/36 is traditionally a CX setup.
I think I would be more concerned with the 46 than the 36.
You could switch your cassette to a 11-28 and that might resolve your concern going from the 34 to the 36.
I run a 46/36 with an 11-32 on my gravel bike, however I am often let down by the 46/11 combo on fast gravel down hills.
Wow. Over 29 mph at a 90 rpm cadence. On gravel.
46x36 is usually used on cyclocross bikes.
^^This^^
I rode this setup before on my cross bike with wider/knobbier tires. When I put some road 28c tires on though I found I ran out gears way too quickly. That being said, I have a bad habit of pushing big gears instead of spinning. (I don’t like a cadence above 80 RPM, but I’m working on that).
I run a 46/36 with an 11-32 on my gravel bike, however I am often let down by the 46/11 combo on fast gravel down hills.
Wow. Over 29 mph at a 90 rpm cadence. On gravel.
I am presuming you did not forget the pink font in your post…
Yes, over 29 mph. On gravel. Speeds of 40 mph + on gravel is not uncommon in fact. And I am not FOP. Based on your compulsion to create this post it sounds like you have not raced gravel and/or lack the bike handling skills to ride at speeds over 29 mph off pavement (or perhaps even on pavement). I suggest you try it sometime, it’s fantastic. **Thank you for your meaningful contribution to this thread. **
A few weeks ago I picked up a Speed Concept 7.8 that has a 46/36 crank set. I’m not sure how I feel it, on the trainer where I spend 99% of my time it is works out pretty well but I’m not so sure about a hillier course like IM Louisville which I’m doing later this year. I come from a 52/36 and a 50/34 of which I preferred the 50/34. I’m a little worried I may run out of options on the steep hills. Can anyone offer a yah or nah on the 46/36? My cassette is 11-26.
I run a 48\36 on my tri bike with a 12-23 cassette, it works fine. Your final drive with a 46/ 11 going downhill will be 4.2 to 1; with a 50/ 11 it would be 4.5 to 1, not a huge difference
maybe take your race bike on a hilly test run ?
I take it that the bike was used. Sounds like someone decided to keep the existing crank (or chainrings) and threw on whatever they had in the parts bin. I’d ditch the 46/36 and go 50/34. You could keep the existing crank and just swap the rings. You could also go the 52/36 route with the existing crank.
Gearing on a bike is usually a personal choice based on where/how you ride. I tend to be more of a masher on my TT bike, so I run 53/39 and sometimes long for a 54t/55t on flat courses. However, I run on 50/34 on my road bike.
I run a 46/36 with an 11-32 on my gravel bike, however I am often let down by the 46/11 combo on fast gravel down hills.
Wow. Over 29 mph at a 90 rpm cadence. On gravel.
I am presuming you did not forget the pink font in your post…
Yes, over 29 mph. On gravel. Speeds of 40 mph + on gravel is not uncommon in fact. And I am not FOP. Based on your compulsion to create this post it sounds like you have not raced gravel and/or lack the bike handling skills to ride at speeds over 29 mph off pavement (or perhaps even on pavement). I suggest you try it sometime, it’s fantastic. **Thank you for your meaningful contribution to this thread. **
No need to get snarky. I haven’t raced gravel, I didn’t know they regularly raced at those speeds on those surfaces - I’m genuinely impressed.
I have one on my cyclocross bike. I used it on the road for two years and was surprised it was not an issue for me even on some fast group rides. I’m not why it would be a problem on a hill ? Flat road with a tail wind may be the only time you run out of gears.
Thanks for the replies. The crank appears to be original since it is SRAM force and the rest of the drivetrain is the same, I’m assuming the previous owner swapped the rings because they live in Florida and wanted more useable gears on the flat terrain without having to drop to the 36. I think I will put a 50 or 52 on but will take it out for a ride this weekend. I found a nice speed calculator on the net that has you put in your gearing and your cadence range and it outputs a speed based assuming not wind or hills. At a 105 cadence a 46/11 puts you at about 32mph and 52/11 gives you about 39mph. I only imagine pedaling 105rpm at that speed on a long (1+mile) downhill which is fairly rare for Ohio and Kentucky. I will probably just put a 50 on it since that’s what my road bike had on it and it gave me a nice range.
I really just wanted to know if this was common gearing for Triathlons since I am new to the sport this year; sounds like there are a number of folks who are running similar gearing.
Thanks
Just to add some data to this, I looked at the files for the 2 gravel events I did last year. In each of them, I spent >30 minutes (out of 4.5-5.5 hours riding time) over 30mph. In one of them (Chino Grinder in AZ, a fairly popular event) I had a 26 minute segment where I averaged 30.5mph.
Long climbs tend to mean long descents, which can mean sustained high speeds. Also, many (most?) gravel events are truly mixed media, meaning they’ve got a substantial portion of paved roads. Besides Chino (which is roughly 40% paved), I did a Rapha event in Boulder a few years ago that was also close to 40% paved.
A 46x11 might be OK for some gravel events, especially if you’re using bigger (40mm and up) tires, but most people tend to run a 48 or 50t big ring so as to be able to pedal comfortably on the faster sections. They also run a 34t small ring, with a 28 or 32t largest cog in back. With 11 (and even 10) speed drivetrains, this is perfectly feasible, and gives you the gearing range you need.
My racing years, at least for bike racing, are pretty much behind me, and if I place in a tri it’ll be in my AG in small races… Anyway, I’m running 46/34 on my road and gravel bikes, with a 11-23 cluster in back (on the roadie), and quite frankly really like it. Keeps the gears close while giving plenty of range for the climbs I see around my home town (Cascade foothills). Nothing wrong with that set of 'rings. I might go to a 48 for tri racing, and if I were back into group road rides that got sporty, maybe a 50.
A few weeks ago I picked up a Speed Concept 7.8…a hillier course like IM Louisville which I’m doing…My cassette is 11-26.
This quickly devolved into everybody talking about the riding they do and not your specific question of a tri bike at an IM.
Realistically, you should probably be tucking and coasting vs. pedaling once you go much over 30 mph. 90 rpm in your 46 x 11 is right on the cusp of 30 mph, so I feel that’s just fine. It’s really the 36 front and 26 rear that would concern me more. I have no idea what your watts/kg threshold is, so I can’t really comment on the climbing gears. Have you done an IM before? Which one? How long did it take to do the bike leg? That may give us a better idea of how much low end you need. For most people, it’s just a long day of conserving energy (not flying up hills) and remembering that you still have to run a marathon.
Personally, I think your gearing range is likely okay. If you had to change anything, an 11-28 or even 11-32 cassette you make climbing those steep hills on each loop marginally easy and be done for ~$65. If I remember right, the last 25 or so miles of the bike loop look fairly downhill so you shouldn’t have to worry about steep climbs in the last hour or so. A 34 inner tooth with the 26 rear is about the same gear as the 36 x 28 though. I could see throwing a 50x34 crank on there at some point if you find one you like, but I wouldn’t say it’s necessary right now.
This quickly devolved into everybody talking about the riding they do and not your specific question of a tri bike at an IM.
Realistically, you should probably be tucking and coasting vs. pedaling once you go much over 30 mph. 90 rpm in your 46 x 11 is right on the cusp of 30 mph, so I feel that’s just fine.
I was thinking something similar. There’s a small window on descents, somewhere in the low-mid 30 mph range (depending on comfort/capacity at high cadence) where you’d be coasting when you could be pedaling a little faster with a 50T front ring instead of the 46. But for anything above or below that window, there’s no real difference.
This quickly devolved into everybody talking about the riding they do and not your specific question of a tri bike at an IM.
Realistically, you should probably be tucking and coasting vs. pedaling once you go much over 30 mph. 90 rpm in your 46 x 11 is right on the cusp of 30 mph, so I feel that’s just fine.
I was thinking something similar. There’s a small window on descents, somewhere in the low-mid 30 mph range (depending on comfort/capacity at high cadence) where you’d be coasting when you could be pedaling a little faster with a 50T front ring instead of the 46. But for anything above or below that window, there’s no real difference.
It has nothing to do with OP, but Alan Couzen’s has the best write-up on this I have ever seen. http://www.endurancecorner.com/2015/09/14/know-your-enemy-part-iii-optimal-pacing-for-different-courses/