login
Help Understanding Rear Cogs & Component Groups
-
No new posts
 2014-11-02 10:42 AM |
Member  58  West Linn, Or |  Subject: Help Understanding Rear Cogs & Component GroupsI am shopping for a new bike and have a few tech questions. This is my second road bike. The first I sold a year or so ago when I was having some back trouble and needed the cash. I am ready to get back to riding and and am going to hit the LBS this coming week. I have been looking at bikes online and have a few that I am interested in looking at and have a few questions about component groups. I am hoping to get a bike with Tiagra components but I am on a tight budget. I live in a very hilly area and am concerned with the lower gear selection of the Claris and Sora groups but the price point is attractive. Is it safe to assume that a Claris equipped bike is not going to climb as well as a Tiagra equipped bike due to the lower gear count? What factors affect a bikes ability to climb? I notice the rear cogs seem to specified differently. 12/30, 11/28,12/25..... Is that number dictated by the chosen component group and what, if any, affect does it have on climbing ability? A Cannondale CAAD 8 with Claris components is advertised for $799 at my local LBS. If I went that rout and decided down the road that I wanted to upgrade to say 105, roughly how much do you think that will cost? $500? Thanks, Matt |
| 2014-11-02 3:50 PM in reply to: #5064685 |
| 23 | Subject: RE: Help Understanding Rear Cogs & Component Groups If you live in a hilly area and plan to ride lots of hilly rides then you're best getting a compact chainset (50/34) and a rear cassette with the largest sprocket at least a 28. Don't worry too much about the groupset and lower gear count - this won't affect your easiest and hardest gears, but will mean the jumps in between may be quite large. A 9 speed cassette will be fine though - and if it means you save a bit and get a better bike then all the better. You can upgrade to 105 in the future- either the 10 speed version or even the new 11 speed. The only change you may have to make if you bought a bike with 9 speed is that the rear wheel hub may need changing. But if you're planning on upgrading then you'd probably just buy a new wheelset (maybe Mavic Aksum or Equipe, which aren't very expensive) at the same time as your new groupset. Hope this helps |
| 2014-11-03 10:03 AM in reply to: KETri |
Member 58 West Linn, Or | Subject: RE: Help Understanding Rear Cogs & Component Groups Thanks, That does help. What is your opinion on a triple vs compact crank? Matt |
| 2014-11-03 12:08 PM in reply to: mcyork37 |
Pro 6582   Melbourne FL Gold member | Subject: RE: Help Understanding Rear Cogs & Component Groups Originally posted by mcyork37 Thanks, That does help. What is your opinion on a triple vs compact crank? Matt With a compact and 32 rear cog you should be able to climb just about anything! Triples, especially from a low end group (shimano doesn't offer on higher end groups anymore), can be a bugger in regards to tuning. I had a triple on my 1st entry level RB and it was finicky thing, hated it. Couldn't believe the difference with a nice double FD.For reference take a look at this site http://www.bikesdirect.com/products/road_bikes.htm, in particular the 105/Tiagra row. The 2&3rd bikes in show bikes with the brand new 105 11-spd groupset using 11-32 cassettes & compact cranks. No need to upgrade anything later. I've ordered from BD before and it comes mostly assembled with a few things to do (did it myself). I ordered my brother a bike before and he took it to a bike shop to finish the build up. If you know what size fits you (they offer guidelines) then its a good option to go for getting the most out of your $. |
| 2014-11-03 1:02 PM in reply to: mcyork37 |
Veteran 2297  Great White North | Subject: RE: Help Understanding Rear Cogs & Component Groups Go microshift at that price point. |
| 2014-11-03 1:53 PM in reply to: mcyork37 |
| 467 , Wisconsin | Subject: RE: Help Understanding Rear Cogs & Component Groups Matt, if your interest is primarily competing in Tri I would probably stay away from triples. As others have said, they can be a bit of a pain to tune. And, when racing you've got to deal with three sets of combinations instead of two. I'm not sure how hilly it is where you live, but we have quite a bit of 6-12% grade around here that can be anywhere from 1/4 mile long to about a mile. I'm 60 and I rarely need anything lower than 34-24. Occasionally I'll use 34-28 for the really steep stuff or if I'm tired. I personally think triples are more suited to long-distance touring, often with heavy packs etc, or just casual riding. Another possibility is that $750 can often buy a pretty nice barely used, almost new bike that would retail for about twice that . . . |
| 2014-11-03 3:51 PM in reply to: #5064731 |
| 23 | Subject: RE: Help Understanding Rear Cogs & Component Groups Yeah I also wouldn't worry about getting a triple. If you're going to be doing tris then you'll probably hitting a tempo pace and won't ever need that small inner ring. Have a look at an online gear ratio calculator for the type of gearing you might need. If you know the type of cadence you'll likely ride then you can see your maximum and lowest speed at the cadence. The lowest speed is the one you want to look at for the hills- but I'm pretty sure that 34/28 will get you as low as 5 or 6 mph at a relatively comfortable cadence. |
| 2014-11-03 6:34 PM in reply to: KETri |
Member 58 West Linn, Or | Subject: RE: Help Understanding Rear Cogs & Component Groups Thanks for all the feedback. I test rode a few bikes today and have a couple more I would like to look at. I have been watching Craigslist pretty closely for a used bike but haven't found anything in my size that I am interested in. |
| 2014-11-04 6:29 AM in reply to: mcyork37 |
Champion 7547 Albuquerque, New Mexico Bronze member | Subject: RE: Help Understanding Rear Cogs & Component Groups Not sure if anyone answered your actual question. For the chainrings (front gears), the smaller the number the easier to pedal and the higher the number the faster you'll go. Thus a standard 53/39 is harder to pedal but gives you potentially faster speeds than a compact 50/34. For the cassette (rear gears), the smaller the number, the faster you'll be able to go and the larger the number the easier it is to pedal. A 12-23 and a 12-25 will give you the same top speed but you'll have a slightly easier lowest gear for climbing hills with the 12-25. A 12-28 or 13-30 would be even easier when climbing but you won't be able to go as fast on downhill. Top speed is kinda theoretical in that you will rarely be in your highest gear unless you are descending. Does it really matter if you go 50.0 km/hr or 51.1 km/hr pedaling at 90 rpm down a hill? How often when you ride would you hit speeds like that? I averaged 29 km/hr on my race recently and never during the 180 km shifted into my highest gear. If the gearing is the same, there is no difference between a Sora, Claris, Tiagra, or 105 drivetrain as far as climbing hills or top speed. Shift quality may be different, but even that may be hard to discern. There are guys on BT who have put 10,000 km on Sora equipped bikes. |
| 2014-11-04 7:18 AM in reply to: mcyork37 |
Extreme Veteran 1986 Cypress, TX | Subject: RE: Help Understanding Rear Cogs & Component Groups Originally posted by mcyork37 Thanks for all the feedback. I test rode a few bikes today and have a couple more I would like to look at. I have been watching Craigslist pretty closely for a used bike but haven't found anything in my size that I am interested in. You can get some amazing deals on barely used bikes on Ebay and Craigslist. I bought a once ridden 2014 Specialized Tarmac SL4 with 11-Speed Ultegra components for $1800 earlier this year. That's about half price. |
| 2014-11-04 8:03 AM in reply to: McFuzz |
Member 58 West Linn, Or | Subject: RE: Help Understanding Rear Cogs & Component Groups Thank you for the detailed explanation McFuzz. That really helps a lot. |
| 2014-11-04 3:54 PM in reply to: KETri |
Member 58 West Linn, Or | Subject: RE: Help Understanding Rear Cogs & Component Groups Thanks for all the feedback. it really helped. I ended up buying a Cannondale Synapse 6 with the Tiagra group, a compact crank, and a 12/30 cassette. (Synapse.jpg) Attachments ---------------- Synapse.jpg (1432KB - 1 downloads) |
| 2014-11-04 5:18 PM in reply to: mcyork37 |
Veteran 2297 Great White North | Subject: RE: Help Understanding Rear Cogs & Component Groups Do you need pedals?? I can give you some Mtb SPD if you want to pay shipping. Maybe $15. |
| 2014-11-04 5:34 PM in reply to: simpsonbo |
Member 58 West Linn, Or | Subject: RE: Help Understanding Rear Cogs & Component Groups I appreciate that offer but I already ordered some Shimano SPD pedals off ebay. I still have my old shoes with cleats. |
| 2014-11-05 12:25 AM in reply to: #5065009 |
| 23 | Subject: RE: Help Understanding Rear Cogs & Component Groups Nice bike! And great set up with gearing for what you need. I doubt you'll ever find yourself without the gear you want on that given the type of riding you'll be doing. Enjoy! |
| 2014-11-05 6:48 AM in reply to: mcyork37 |
| 467 , Wisconsin | Subject: RE: Help Understanding Rear Cogs & Component Groups Nice looking bike! Enjoy the heck out of it . . . |
| 2014-11-05 8:32 AM in reply to: mcyork37 |
Champion 7547 Albuquerque, New Mexico Bronze member | Subject: RE: Help Understanding Rear Cogs & Component Groups Nice bike. WheelRPM = CrankRPM*(RearGear/FrontGear) Speed = WheelRPM*Circumference*60/1000 Assume 90 RPM cadence (CrankRPM), 30 RearGear, 34 FrontGear, & 2.096m wheel circumference (from my Cateye manual for 700x23C) you get 12.8 km/hr. Pretty much, with that gearing you can climb hills like a mountain goat! |
| 2014-11-05 4:47 PM in reply to: mcyork37 |
| 1055 | Subject: RE: Help Understanding Rear Cogs & Component Groups |
|
|
|
|
View profile
Add to friends
Go to training log
Go to race log
Send a message
View album
CONNECT WITH FACEBOOK