johngwheeler

I've spend some time comparing the geometry of my two bikes, both of which I bought before I properly understood what bike geometry meant to handling and ride quality. I have a Giant TCX and a Trek Crossrip.

I've played around with the fit, so that both bikes have very close saddle heights and saddle-to-bar distances, but they feel very different to actually ride.

I'm actually more comfortable, and feel safer, on the Trek, despite it being the cheaper bike (half the price of the Giant), but recognise that it's a slower and less agile bike - that also has a rougher ride due to the aluminium frame vs the carbon of the Giant.

But I'm interested in what makes the Trek feel more stable and composed, and I'm guessing that it's mostly geometry.

Here's a summary of the two geometries:

Screenshot 2017-05-18 17.28.51.jpg

The Trek has a longer wheelbase (1043 vs 1019mm) and lower bottom bracket (74mm vs 60mm), and from what I've read, both of these will aid the feeling of stability, particularly on corners.

Interestingly I feel quite a bit more stretched out (on the hoods) on the Giant, even though the reach is 20mm shorter than on the Trek. I don't think the stems are that different in length (but maybe a centimetre).

I particularly notice that I feel far further forward over the front wheel on the Giant, and when standing, the bike feels much more twitchy. Is this due to total wheelbase, or the "front center" measurement (front axle to BB?) which is not listed?

I imagine that the shorter overall wheelbase and shorter chain stays are more in keeping with a race geometry (for CX races), so would I expect something similar on any bike designed for this use (or a road bike)?

How many of you also have road bikes, and do you find you have to adjust your technique when you move from a more relaxed gravel grinder geometry to the road bike?

John.

Spoonrobot 

Could be the wheels and tires too.

And don't forget when you measure reach you want measure the actual reach as well to account for handlebar reach and shifter reach; which can vary by 20-30mm easily.

DrIsotope

Giant is more compact, so your weight is closer to the bars. That Trek is really stretched out. It has just 10mm shorter wheelbase than my 59cm Ritchey, which actually sizes comparably to other mfrs. 61cm frames. When I stand and pedal, my knees only miss the bars by about 20mm-- my frame is very compact. Crossrip also not especially spritely in the weight department, perhaps some "butt dyno" in effect here, where the heavier bike feels more stable?

fietsbob

Favorite would be made to measure.. but you want shopping help for stock frames.

no comment.








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johngwheeler

That's a really good point! The Trek has a rack and pannier when I commute, and all up weight is > 16kg. The Giant is propbably only 10kg with the usual lights/saddle bag etc. Perhaps I should stick some weights on to Giant and do a test....

Kapusta

Trek also has the slacker head angle.

Atsuico

My wife road the Crossrip and Domane and said the Crossrip felt way more planted, less twitchy, and more comfortable overall. She did say the Domane felt lighter and faster, but that the tradeoff wasn't worth it. She loves the crossrip.

Zurichman2

I love my Lemond frame set ups. That being said when I was looking for my bike years ago I really like the ride of a Merlin ti but don't remember the model.

Zman

johngwheeler

I've now had a couple of longer rides on the Giant TCX and have started to use it for some of commutes (when I don't need to carry stuff).

I think I'm now considerably more comfortable with it than I was first posted this thread. I went back to the Trek Crossrip for a test and it felt very slow and sluggish, so I guess it's all just a case of adapting to different bikes, and with experience, this adaption will be nearly instant every time I get on a different bike.

Probably a lot of my initial concern was just lack of confidence in my ability to handle the bike and the more "reactive" front end steering. I deliberately did some exercises riding out of the saddle and sprinting on the hoods and drops, getting well over the front wheel, which initially scared me a bit. Now that I know I'm not going to lose control, I feel much more confident.

Practice makes perfect!

John.