Skaughtto

I'm a daily cycling commuter newbie who's started to take advantage of the additional daylight by riding off into the mountains after work. Would I experience a noticeable benefit going from my current old triple Tiagra groupset to a newer 105 compact one?

The 30t front ring feels like a bit of a waste, so I wasn't sure if I could get away with 50-34 instead of 50-39-30. Would swapping out the 12-30 rear cassette be a better move?

What's the best way to evaluate this kind of change without wasting my LBS's time?


"Baby's 1st Road Bike" is a 2013 Domane 2.0 T purchased last July.
Wheels - Bontrager Paradigm Comp TLR
Tires - Gatorskin 700x25c

Dave Mayer

Your bike shop will heartily endorse this project. $500 of parts, $300 in labor, plus the opportunity for the mechanics to sell your worthless old components on Ebay for their own beer money.

I am a recent owner of a second-hand KHS road bike with a Tiagra 3 x 9-speed drivetrain. The front and rear shifting is flawless - crisp and precise.

The triple allows me to stay in the middle ring 90% of the time, as opposed to frustratingly and regularly cycling back and forth between the 50 (too big) and 34 (too small) rings on my compact doubles.

The shifting speed and accuracy on the Tiagra is superior to my two 105 11-speed setups. This is due to Shimano moving the shifter cables to under the bar wrap, thereby introducing extra tight bends and cable friction.

11-speed upgrade? You'll need new wheels. Plus be prepared to pay double what you currently pay for replacement chains and cassettes.

TrojanHorse

I'm going to say the exact opposite... I have 11 speed 105 and 11 speed ultegra on two of my bikes and my wife has 9 speed tiagra triple. The feel of the shifters is lighter on tiagra but I prefer everything else about my 11 speed set up, but it's not anything dramatic.

Having said that, it would cost you a ton of money to change out your drive train and you probably would not realize much of a benefit. If you can do the work yourself, a 105 drive train is about $350 from one of the UK outfits. Plus new wheels. Plus chains don't last as long.

So, if you're happy with the shifting on your tiagra set up, keep it! And if you're riding off into the mountains after work, I imagine that 30 tooth chainring will come in handy. Btw, my wife's RD (from about 2010 I think) couldn't take anything bigger than a 26 tooth cog in the back, so I swapped it out for a Deore long cage MTB RD and put an 11-30 cassette in back for her. YMMV

tagaproject6

It really depends on he amount of money you are willing to spend. As long as the LBS gets paid, they are not wasting time.

The question is...what do you want your current gear to do that you feel is not doing right now? If you feel that the current 30 ring is a waste, would you feel better by spending money to change the set up?

AlmostTrick

Since you consider yourself a newbie, the first step before even considering any gearing changes is to RIDE. While riding take careful note of what gears you use, how often you shift, etc. I like to run the gear inches on Sheldon's page to see where I'm at, and where I want to be.

https://www.sheldonbrown.com/gear-calc.html

Only after riding for a while and doing the above would I advise changing anything. If you absolutely MUST spend money/upgrade your bike LIKE NOW, (been there, done that!) then get some new bar tape or maybe a different saddle.

I have to say I couldn't agree more with Dave when it comes to how useful the center ring on a triple is in real life. So much so that I only run one ring on all of my bikes now. Personally, I found the 34-50 to be the absolute worst for me, for the reasons Dave mentioned. But preferred gearing is a very personal thing. What works for best for you may differ greatly. But you won't really know until you ride more!

rms13

What are you trying to accomplish? If the you don't need the 30t ring then don't use it. If the 50/39 chainrings give you all of the range of gears that you need for riding then just use those.

seypat

This. Seems like a waste of money to switch.

Racing Dan

Wise Words.

Just stay with the triple. Maybe consider a different cassette. Hard to tell which. Depends on preference and your particular needs.

GrainBrain

It's just a commuter, don't waste money on it. The nice thing about the triple is you can run a tighter cassette. I would absolutely change to a 12-25 or 11-23. You'll use the triple for sure!

But definitely ride it more to see which gears you use. I think a 3x9 triple is more functional then a double on the mountains.

jon c. 

I ride with a triple and never use the bottom ring. Except for a few times when I visit my brother and ride in the NC mountains. But the gearing works well as is and I see no need to change. As for the derailleurs, I upgraded when I first got the bike and did find the shifting a bit more crisp. It was worth it to me, but I wouldn't say it was necessary.

Skaughtto

Thanks for all the feedback. I'll keep on truckin' with the Tiagra triple until it wears out. When I hit the road again this afternoon I'll pay better attention to the gears I'm using. If you search for "Stevens Creek Reservoir Loop", that's what I'm adding to my ride home from work in Cupertino, CA.

Last time I rode it I felt like I spent too much time looking for the right gear and it felt like the correct one was creating a bad chain line. 34t seemed like the goldilocks option between 30t and 39t, so I started thinking about replacing the triple. Changing the cassette around would certainly be a cheaper/easier swap. I was curious if the shifting would be more precise with 105, but it sounds like it wouldn't be a huge leap forward.

The wheels I have say they are good for 10 or 11 speed. Maybe I'll search around to see if I should be using a spacer or not. I've been doing all my own maintenance and parts swapping(bars, stem, saddle, brakes, cables/housing, headset...), so messing around with the groupset seemed like the next place to tinker, but if it's not worth it I won't bother. Again, I appreciate the advice.

Leinster

Bike Gremlin

Only you can answer your question. Use this tool:

Bicycle Gear Calculator

Enter the gears you use now, see how you would fare with another setup (you can list two setups side by side using that interface, just click the "Compare" button). Will the new setup make you ride cross chained a lot more, or will it fit spot on? Do you have low and high enough gears with it?
Compare with what you have (tested) now and see.

Ratman6161

The gear calculator is a great thing!. I was using that a lot when deciding on a new biike.

My two old bikes are as follows:
2005 Ultegra triple with 52/39/30 crank and 12/25 10 speed cassette I did Ride the Rockies on this if you know what that is. The year i did it was 406 miles over 6 days across Colorado - mountain passes and all.
2007 Ultegra 52/39 crank with 12/27 cassette.

New bike Ultegra R8000 with 50/34 crank and 11/34 11 speed cassette.

on the 2007 with more of a race oriented set of gear ratios, I never really used the fastest two gears other than down hill with a tail wind. Another observation is that the larger two rings on the triple are the same 52/39. When you actually calculate all the gear ratios, the lowest climbing gear on the triple is 1.2:1 where with the compact double its 1:1 and there are actually a total of three gears that are approximately eequal or lower than the small ring in the triple. So the compact inst going to lack climbing gears when I take a trip back to the mountains, Here in Minnesota, I'm on flat ground or rolling hills most of the time and figure I'm going to be in the big ring on the compact crank most of the time. I think that for the majority of people who don't race, the compact double set up is going to be the most flexible.

That said, upgrading a bike is usually a losing game in my book. If you already have a triple and its working for you, I'd just wait until you are ready to buy a new bike and then switch to the compact double. When I first moved to MN from CO and found I wasn't using the little ring anymore, I actually talked to a local shop about converting it. They said they would be happy to do the job if I wanted but gave me the same advice I just gave you. i.e. wait until you are ready to get a new bike anyway. When you start adding up the costs of replacing individual components it adds up so fast its not worth it.

seypat

Is a 34 ring available for the triple crank? If so, get one and swap out the middle ring. Leave the 30 on. Ride it and evaluate. Then make your decision.

Carbonfiberboy 

No. IIRC 36 is the smallest 110 BCD ring. But as above, if you never shift into the 30, you'll love the 11 speed. If you need the 30, don't change. I do long pass climbs in my 26 ring X 27 cog. You can get inner rings down to 24T, but with smaller than 30T inner rings, one needs to change the middle to a 39T and the outer ring to a 53T that's meant to go on a double.

HTupolev

5-bolt 110BCD rings are commonly available down to 34T. 33T ones also exist, although they're rare.

Bike Gremlin

One problem with the market (at least for my taste) is the lack of (reasonably priced) cassettes that start with 13, or more teeth. For a "modern" compact 50-34 cranks to work for me, without severe cross chaining, I'd prefer a 13-32 cassette. However, most 13 and 14 T starting ones are sold as "junior racing" and cost a premium price, without being widely available where I live.

But it is how it is - any gear calculations I do with 11, or 12 T starting cassettes in mind and see what works with those. Both in terms of gear ratio, gearing "gaps" and chain-crossing.

Ratman6161

I don't quite see the cross chaining issue. The way I look at it is as follows: On the big ring (50) the biggest three on the cassette - 27,30, and 34 aren't usable since it would be cross chaining. On the small ring (34), the smallest three on the cassette - 11,13, and 15 aren't usable.

So the slowest usable on the big ring is a ratio of 50:25 and the fastest usable on the small ring is 34:17 i.e. both 2:1.

When I compare this to my old bike with 52/39 and 12-27 ten speed, the slowest climbing ratio would be 39:27 or about 1.44:1...about equivalent to 34:23 (1.49:1) on the compact. What this means is that in Minnesota, I'm not really very likely to be using the small ring very much and the only ratios I'll use it for on a regualr basis are 34:19 and 34:21. On the other hand when I go back to Colorado for a visit I'll have 4 more climbing gears that are lower than the 39:27 and go lower than my old triple which had 30:25 as its best climbing gear at 1.2:1.

But...I do sort of agree on the gaps. The 50:11 ratio isn't really worth anything to me and a cassette that started at 13 would give me closer ratios on the gears I do use. The Shimano web site shows Ultegra cassettes available in 11-25T 11-28T 11-30T 12-25T 14-28T 11-32T and the HG-800 at 11-34. For your purposes, why not the 14-28? That would give you a best climbing gear of 50:28 (1.21:1) or about the same as the old triples.

Racing Dan

The cross chaining issue with the 50/34 is real (to some). Combined with a 11-28 you may find yourself cycling back and forth between "big-big" and "small-small", depending on terrain and your strength. With the 11-34 the middle gears are pushed two over compared to 11-28. Your middle cog is a 21t, but on the 11-28 its a 17t.

banerjek

If your 30T feels like a waste, it's a sign that your gearing is not optimal.

I personally don't buy into the "just a commuter" logic. There's a lot to be said for dialing in the bike that gets ridden day in and day out where you put in your real hours and miles.

I also would be careful about what you can get away with. 50/34 is versatile, but there's a lack of mid range for the moderate speeds that many people ride with while carrying gear so there's more ring switching than desirable. I believe the 46/36 combo is underrated. It offers more overlap allowing a tighter cassette with better selectivity. Unless you have steep hills or regularly encounter strong head or tailwinds, having a lower bottom end or a higher top end isn't beneficial and costs you cogs that you could otherwise use.

Skaughtto

I took the same route again on Friday afternoon and did much better since I knew where I was going along with what to expect. The 10-15% grade .4mi climb came as a surprise the first time I did it, but it was way more manageable this time around, plus I was super mindful about my gearing. My most direct one-way commute is short(6mi) without any climbing. I carry a backpack with maybe 5lbs of stuff at most, so I'm not hauling anything extremely heavy for very long, which is why I'm adding miles. The longer route I took on Monday and Friday was about 18mi with 800ft of climbing.

That gear-calculator site is definitely a good planning tool. It really helps show that the 39t middle gear is a bunch of overlap and I'd only be losing the 30-30. 34-27 looks equivalent to the next lowest gear I currently have, so I think I'd end up ok if I did switch parts around or get another bike with a compact. I'll have to play around with more setups.