Trek Domane SL4 VS SL5
 

Hi all,

Long time mtn and gravel rider here and looking into my first "proper" road bike. I'm wondering if you can help me understand the difference in the 2020 Trek Domane SL4 and SL5 builds. The price difference is $500 and from what I can tell the big difference is 11 speed vs 10 speed. How important is that on a road bike? Other than the number of gears, do you think I would notice a difference anywhere else? Shifting, braking, etc (weight is the same for both models)?

On one hand it's only $500 clams and on the other it's $500 clams.

I'll be doing a ride or so a week on it, pavement, 3 hours each.

Thanks for the help, these component sets are all new to me.

-Kyle


SL5 SL4

Shifters Shimano 105 R7020, 11 speed Shimano Tiagra R4720, 10 speed

Front derailleur Shimano 105 R7000, braze-on Shimano 105 R7000, braze-on

Rear derailleur Shimano 105 R7000, Shadow design, long cage, 34T max cog Shimano Tiagra 4700, long cage
CrankShimano 105 R7000, 50/34 (compact) Praxis Alba M30, 50/34 (compact), 30mm spindle

Bottom bracket Praxis, T47 threaded, internal bearing Praxis, T47 threaded, internal bearing

Cassette Shimano 105 HG700-11, 11-34, 11 speed Shimano Tiagra HG500, 12-28, 10 speed

Chain Shimano 105 HG601, 11 speed Shimano Tiagra HG54, 10 speed


Brakeset Shimano 105 R7070 hydraulic disc Shimano Tiagra R4770 hydraulic disc

Huh. I hadn't seen that they'd started offering the Domane SL in Tiagra - that's cool.

You should still be able to get the gearing range that you need/want in 10sp. Usually the extra cog in an 11sp system is going to mean slightly tighter spacing within the gearing range; if you're racing or participating in spirited group rides, a gearing gap at the wrong place and at the wrong time can sometimes make the difference between hanging on and dropping off, but we're really picking nits. It's a non-factor most of the time for most people.

The biggest reason to get in to 11sp is just the upgrade and replacement path - being able to interchange a lot of the 105, Ultegra and DA parts will give you some flexibility.

I also see that the SL4 comes with a Praxis crankset - this doesn't concern me at all, Praxis makes some nice stuff. I think that this should actually give you a nice, affordable (relatively speaking) power meter option with Power2Max. You could add single-sided power to the 105 crankset for $600 or so, but the P2M would gauge total power for $490 (if this is something that you would be interested in, double-check compatibility before taking my word for it, though).

I haven't tested Tiagra, but given Shimano's trickle-down, I assume that it's shifts as nicely (or better) than the 105 of previous generations, which has been very good, indeed (5700 was a bit of a step backwards, but I digress); I would be very skeptical that someone could tell the difference in shifting quality between the two, ditto for the braking.

I had essentially the same decision between 105 and Ultegra when I bought mine...went with the nicer group, which happened to include nicer wheels as a bonus. What it gets you on the SL5 in addition to 105, is a 11/32 cassette...really nice in hilly terrain. Color choice may be a factor for you as well.

An 11-32 is available in 10sp, too, so a $40 consumable that takes 3 minutes to swap is hardly a good reason for a $500 upgrade.

Thank you for the detailed response WhyFi, much appreciated.

The difference between 10sp and 11sp isn't all that important. They do have a much much lower cassette gear on the SL5 (11-34 vs 11-28). This is about a $50 change and would be important if you've got long, steep hills in your area.

The SL5 has fancier paint.

If you want to a power meter, the Shimano 105 crank will be easier to get a cheap crank arm PM than the Praxis unit. It would be about $150 more to change the crank or get a PM for the Praxis setup.

They both have very basic tires and wheels, so putting on a set of faster rolling tires would be an instant upgrade in speed to either of them. Otherwise, besides the hill gearing and tires, they are equally speedy.


Otherwise, that's it.

Awesome, thanks. Since I prefer the color scheme of the SL4 maybe I'll just put the $500 difference towards tires.

I haven't looked at single-sided PMs lately - what's cheaper than the $490 Power2Max NGeco spider that would pop on to the Praxis crankset?

A Tiagra crank, BB, and a Stages, 4iiiiiiiiiiii, Pioneer 105 on sale OR a Favaro(sp?) single side on sale.

Maybe $60 in tires lol
spend the rest on other awesome stuff

Ah, you're talking closeout/sale priced vs regular price of the P2M, so not apples-to-apples. Yeah, I'd rather have the complete power measurement (vs single-sided and an assumption) unless it was a significant savings.

P2M doesn’t go on sale historically. Last year they offered free rings. The FSA powerbox does, but I don’t recommend it. ... and there no same in buying something on sale.

P2M makes an excellent product - I’ve had 2. If you’re arguing with yourself about it, It will last 10 years, be unflappable, and resell well.

Theres no reason to go crazy for dual sided unless you are doing short sprints or clearly have a mangled leg. You put about 20lbs of force on the pedals, so even a bad leg can do that. Dual sided only highlights how straight your saddle is and how often you lead off with on leg or the other. You’re not going to exercise your way to 50/50 if you’re number is off.


Back to the bike - buy the one with the paint you like.

Def get the color you like the best, that's a hard thing to change, you can always swap wheels and components later. :thumb:

Good choice on the Domane. It's a great riding, comfortable bike that's versatile due to the ability to hold wide tires. My wife is getting one (SL5 trim) for Xmas (shhhh).

As for 10 vs 11 speed, I would push you hard towards 11 speed IF you had any other road bikes that were 11 speed because it's nice being able to swap wheels and components if necessary. But since this is your first road bike, the 10 speed is fine and Tiagra works well. The higher level group sets are better, but you won't notice those difference as a new road biker and, even then, the differences may be hard to discern unless you ride them back to back.

As mentioned above, you can always upgrade to a different group set later if you want, and even do it in stages if you're up to doing the work yourself.

I’ll give my 2c

My Specialized bike came with a Praxis Alba crank and the shifting was horrible. The chain would rub in a bunch of gears. Shifting from the little ring to the big ring was extremely unreliable. My shop simply couldn’t fix it and refused to warranty it. They told me to get a Shimano crank if I want decent shifting. I thought that was part of the deal.

So I did, and it fixed almost all my issues. I think my FD hanger might be slightly messed up from 6 months of constant adjustment but unfortunately it’s not replaceable.

So I would 100% factor in the cost of a Tiagra crank and T47 Shimano BB into your purchase. That’s about $150. Not the worst in the world. That being said, maybe the Praxis crank works better with 10 speed stuff than 11 speed stuff. Who knows?

It’s also worth noting that some people had issues with the “long arm” FD design on Tiagra (and old 105/ult/DA), depending on frame geometry. It shouldn’t be much of an issue, hopefully.

One nice thing is that the SL4 comes with Shimano Tiagra hydro shifters and brakes - the good looking ones. So the gap between 105 and tiagra has been narrowed considerably.

Thanks to everyone for the help. What a great community. $500 bones for tires, bike fit, lights, etc will be nice. You guys rule.

If you have any interest in a 2019 SL5 you could possibly negotiate for less than the 2020 SL4. Trek still has some sizes in stock.

This is the primary reason I wouldn't consider the Tiagra version of this bike. Once you are stuck in 10-speed land, it becomes prohibitively expensive to upgrade components, since you would need new hydraulic brifters to go up to anything 11-speed (105, Ultegra, or DA). But with the 11-speed 105 included on the SL5, you could incrementally upgrade individual components to Ultegra/Dura Ace as they wear out or break, or if you are running out of ways to shed grams.

But of course, 12-speed may be on the near horizon anyway...

Based on very faint murmurs I have heard on the internet, I think next gen Tiagra may still be 10 speed. At the very least, Sora would be 10 speed, and it is not bad at all. Hopefully proper hydro disc trickles all the way down.

Spider PM is also single side measurement because the PM can only guess where one side starts and other side ends. For true double you also need a crankarm PM on the left

nothing plastidip can't fix

I've ridden Trek for 36 years. Been on Domane's since 2014.

There are three major differences between the two 2020 model bikes.

1. Eleven-speed v ten-speed,

2. Tiagra v 105 drivetrain

3. The cassette gearing---28t v 34t easiest gear


All three categories on the SL5 are better than the SL4.

The eleven-speed v the ten-speed is by far the least important IMO.

The 105 drivetrain is much better than the Tiagra. (IMO the 105 is the best value FOR THE DOLLAR offered by Shimano/Trek.)

The big cassette 34t on the SL5 is WAY better than the 28t on the SL4. If you do any serious climbs and especially climb that include some steep grades, as in double digit grades that 34t is an ALMOST must have. The older and or heavier you are the more important it becomes.

Speaking for myself and my priorities I would not even consider the SL4 but would get the SL5.

No. Spider PMs aren't dual-sided, and I was very deliberate in not stating that they were, but that doesn't mean that they're single-sided. Single-sided PMs measure one side and then double it, giving you a total power estimate. Spider PMs don't do this - they measure total power (though they can't accurately attribute L/R contribution).

I agree with your analysis. I'm waiting on delivery of a 2020 Domane SL5 as we speak.

If I bought a road bike with a 34t on the back, it would be the first thing to get replaced.

Gearing is only better if it better suits a rider's physiology, terrain and riding habits. Even though I'm a bigger guy, there aren't enough climbs near me that are steep enough and long enough to warrant a 34t. At the same time, I do frequent group rides where I'm at or near threshold, so tight spacing is a huge benefit; a 2- or 3-tooth gap in the wrong place and at the wrong time could mean the difference between hanging on or getting dropped.

And, at the end of the day, we're talking about a consumable part that costs ~40 bucks. That's an incredibly minor consideration when it comes to new bike purchase.