Rear Trek IsoSpeed experiences

Discuss light weight issues concerning road bikes & parts.
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nemeseri
Posts: 786
Joined: Tue Apr 07, 2015 5:40 pm

by nemeseri

Long story short, I'm thinking about buying a Trek Checkpoint bike. The carbon version has rear IsoSpeed, but it can't be adjusted to be firmer than the factory default. I saw a few opinion on the web where people complained about too much flexing, especially on pavement.

IsoSpeed has been around for a while now. Does anybody have issues with too much flexing or moving around too much on the saddle during hard efforts?

If there is too much flex, maybe it's better to go with the alloy version of the frame. I plan to use the bike both on gravel and pavement and I've never had issues with comfort or the compliance of a frame. (I guess this might has something to with my relatively low weight (<60kg / < 130lbs)).

by Weenie


plpete
Posts: 554
Joined: Thu Dec 22, 2011 12:39 pm
Location: DC

by plpete

Not sure how true this is but I feel not all rear IsoSpeed set ups are equal. I own the Madone 9 RSL and Trek Boone and have ridden the Domane on a 20 mile climb. I really like the set up on the Madone and I think it does what it's supposed to. I never experienced too much flex, at least at my weight - 164lbs. It feels firm and takes out the big hits well.

The Boone feels like it has slightly more flex but given that I ride it mostly off road it's a welcome addition. I don't find it bouncy but then again that might depend on your weight.

The Domane seemed to provide the most flex when I rode it. It still felt very stiff when climbing (i think thru axles helped) and the comfort was welcome. I think it all kind of makes sense as those are 3 very different bikes for different types of riders.

With Checkpoint I would assume the flex could be something between a Bonne and Domane but no better way to find out then a test ride!

Geoff
Posts: 5256
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

"Suspension for road bikes is a gimmick designed to get consumers to open their wallets wider. All it will do is add weight and make the bike feel like crap." That's what I though for years. Then I got a Domane and a Madone from my friends at Trek Segafredo and a couple of Boones from Sven Nys and Katie Compton. I could not have been more wrong.

Are the IsoSpeed frames stiff? Yeah, they are plenty stiff. I am only 59kg and produce 1,200 watts in a sprint, so by no means a powerhouse, but each of those bikes is really solid in the bottom bracket and the headtube, despite the IsoSpeed (well, the Boone I have from Sven is from his last season and does not have IsoSpeed in the headtube, so I really cannot speak to that, but Compton's bike is a prototype from Worlds last season and does have IsoSpeed up-front and my wife says that she can really feel it). That Madone is like a rock in the bottom bracket. It is every bit as stiff as a conventional aero carbon race bike. Overtall, I would say that you certainly don't 'feel' IsoSpeed from the standpoint of lack of stiffness.

Does it work as-advertised? In my opinion, IsoSpeed makes the uncomfortable very tolerable. It takes the 'sting' out of bad roads, leaving you fresher over the course of a long ride. As I get 'older', I have grown to appreciate the ride of the old steel bikes of my youth more and more. The IsoSpeed bikes feel like that.

Does IsoSpeed add weight? You bet it does, but I think that you also have to consider the applications. The Domane is build for Paris-Roubaix. For that sort of terrain, you aren't riding the lightest equipment possible anyway, as finishing is more important and the chances of a failure of lightweight kit is higher. In 'cross, it is similar. In both of those disciplines, the softer ride offered by IsoSpeed is fantastic and worth the penalty. If I had to guess where IsoSpeed would be a grudging benefit, I would have said pave and 'cross. I don't think that I would have guessed where it really matters to me most: the aero bike.

I have a number of aero bikes in my collection. Due to the tube shapes, those bikes are real boneshakers. A small guy like me gets really beat-up over 150+km. I feel it in my hands, in particular, for hours afterwards. If you have ever experienced that, the Madone is the bike for you.
Whatever they have done really takes the 'edge' off of long rides. Aero has become downright comfortable.

Yes, these bikes are heavier. In the past, that might have really bothered me, but now I would rather ride the comfy bike.

nemeseri
Posts: 786
Joined: Tue Apr 07, 2015 5:40 pm

by nemeseri

Geoff wrote:
Sat Dec 15, 2018 12:49 am
Does it work as-advertised? In my opinion, IsoSpeed makes the uncomfortable very tolerable. It takes the 'sting' out of bad roads, leaving you fresher over the course of a long ride. As I get 'older', I have grown to appreciate the ride of the old steel bikes of my youth more and more. The IsoSpeed bikes feel like that.
I really appreciate your first-hand opinion and insights on this. My main worry is not frame stiffness, but any bouncing effect the isospeed might introduce on pavement. I will head over to the shop and try the alloy and carbon version to see if I can feel any difference.
plpete wrote:
Fri Dec 14, 2018 11:26 pm
Not sure how true this is but I feel not all rear IsoSpeed set ups are equal. I own the Madone 9 RSL and Trek Boone and have ridden the Domane on a 20 mile climb. [...] With Checkpoint I would assume the flex could be something between a Bonne and Domane but no better way to find out then a test ride!
Unfortunately they have different isospeeds for different models. Some of them are adjustable and some not. I have no idea how flexible the checkpoint isospeed is. I will make sure I test ride one before I buy.

jlok
Posts: 1019
Joined: Tue Jun 30, 2015 3:30 am

by jlok

If you need high saddle height but selected smallest frames, the seatpost would be exposed quite a lot and bouncing may happen sometimes. I got used to it with my smallest size Domane 4.5 Disc Brake and 74cm saddle height. It's really a great bike despite the hefty weight.
Litespeed T1sl Disc / BMC TM02 < Giant Propel Advanced SL Disc 1 < Propel Adv < TCR Adv SL Disc < KTM Revelator Sky < CAAD 12 Disc < Domane S Disc < Alize < CAAD 10

nemeseri
Posts: 786
Joined: Tue Apr 07, 2015 5:40 pm

by nemeseri

jlok wrote:
Sat Dec 15, 2018 6:18 am
If you need high saddle height but selected smallest frames, the seatpost would be exposed quite a lot and bouncing may happen sometimes. I got used to it with my smallest size Domane 4.5 Disc Brake and 74cm saddle height. It's really a great bike despite the hefty weight.
This is interesting. I have short legs and I want relatively short stack too. So I will buy the smallest frameset with the high topcap. I will be close to the max rail height speced on the frame. Interestingly I won't be able to test the bike in my size. :(

jlok
Posts: 1019
Joined: Tue Jun 30, 2015 3:30 am

by jlok

Don't worry too much. You will be fine with it.

First ride: wow! its magic carpet.
First climb: eh... quite heavy but plenty of stiffness to make it to the top.
First descend: wow! on rail!
Litespeed T1sl Disc / BMC TM02 < Giant Propel Advanced SL Disc 1 < Propel Adv < TCR Adv SL Disc < KTM Revelator Sky < CAAD 12 Disc < Domane S Disc < Alize < CAAD 10

73Bronco
Posts: 38
Joined: Sat Oct 28, 2017 6:57 pm

by 73Bronco

I'm about 185 lbs and on a Domane with the non adjustable ISO decoupler. The only time I noticed any bouncing was when combined with a saddle that had some flex built into it. It was some sort of Sella Italia, forget the exact model. Other than that, it's pure comfort.

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SilentDrone
Posts: 191
Joined: Fri Sep 22, 2017 5:55 pm

by SilentDrone

I’ve been on a Domane SLR with the adjustable rear since spring. I’ve had no problems at all. Comfy yet stiff as all that in the bottom bracket. Just as advertised. I have not experienced any bouncing at all. I’m 6-4 and 185 lbs. I’m on a size 62cm. I have mine set at full comfort and I just leave it there. IMO, there’s no reason to set it to be more stiff because that just cancels out the reason for having the isospeed in the first place.


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nemeseri
Posts: 786
Joined: Tue Apr 07, 2015 5:40 pm

by nemeseri

Thank you all! It’s pretty awesome to hear that there are so many happy isospeed users. :)

MisterNoChain
Posts: 174
Joined: Sun Nov 13, 2011 9:29 pm
Location: Belgium

by MisterNoChain

I bought a Domane back in 2012 and it has always been a pleasure to ride. The only downside of Isospeed i could find was when i used it on my Kickr. When i was doing some high cadence intervals i could really feel the flex, when you start to fixate on the flex it gets annoying :). Outside i never had the feeling there was something flexing, it was just pure comfort.

I think you get the most benefit out of Isospeed on a gravel or cyclocross. So i'd definitely go for a carbon frame with Isospeed in that case!

rmr40
Posts: 55
Joined: Sun Aug 07, 2016 9:32 pm

by rmr40

I’m thinking of replacing me SS EVO hi mod with a Domane SLR rime brake but was concerned about the weight of ISO speed - does anyone have any real world frame and fork weights for the SLR?


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nemeseri
Posts: 786
Joined: Tue Apr 07, 2015 5:40 pm

by nemeseri

rmr40 wrote:
Sun Dec 16, 2018 10:47 am
I’m thinking of replacing me SS EVO hi mod with a Domane SLR rime brake but was concerned about the weight of ISO speed - does anyone have any real world frame and fork weights for the SLR?
The weights published by Trek are pretty accurate. I think it will be a bit tricky to build that bike to be under 15lbs with clinchers. You can check out the weight of the bikes on Trek's website and the weight savings with rim brakes should be somewhere 500g-650g.
It's not necessarily because of the weight of the IsoSpeed. In general that bike was designed to be comfortable rather than light. :noidea:

by Weenie


jfranci3
Posts: 649
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Looks like I'm in the same boat here.... My Crockett frame might be warrantied. Dealer says I should be able to move over to Checkpoint, as they'll credit the value.

Concerns: I've found I'm usually in sandy areas - any issues with the ISO setup with sand? The CF units have a shield setup underneath, this isn't a big deal as I can get a similar setup that bolts to the underside water bottle bolts, right?

So ALR vs SL differences:
1) ISO Rear
2) Rear Stay cable routing
3) TT bottle bosses
4) Underside shield
5) 40c vs 45c rear tire (by trek stds, which are 4mm smaller than others)
6) BB86 vs BB90
7) 230gr
That's it, right?

I'm leaning toward SL, for the ISO rear. This will be a #2 road bike to my Emonda ALR Disc. I'm thinking the cushier rear will make for a better long ride / travel bike than the rigid rear on road tires.

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