Geometry Question
 

How much difference is 2 degrees in the head tube angle going to make? One bike has a headtube angle of 74.7, the other 72.7 - all other measurements are the same.

Thoughts? Thinking of a bike for use on the street rather than the track, though I would like something with fairly snappy handling.

Thanks for your input.

it will be very noticeably different. if you want snappy, go for the 72.7 (or did i mix it up...)

It'll make somewhat of a difference, but both bikes will be plenty agile. Best case scenario as always is to test ride the bikes first, bu if not there's really no way of knowing which you would prefer. In that case, I'd just flip a coin.

erm...

Two degrees difference is pretty significant for road bikes. A steeper angle will result in quicker handling. So if you want snappy, get the 74. That being said, test ride both. You might like the one with slightly slower handling more.

Test riding is likely not an option ... though I guess I could find some bikes with similar geometry to test ride. I'd secure in knowing what size bike I need, so my only concern is the handling difference between the two ... ugh. I know I would like snappier handling than my road bike - how would I determine the headtube angle on that?

Thanks again for tolerating my vague and noobie questions.

Head tube angle alone is meaningless without fork rake added in as well. You want to look at the trail measurement (which is determed by HT angle and rake) and the wheel base. A tighter wheelbase and lower trail will result in 'snappier' handling, if such a thing exists...

The math part about bikes makes my head hurt.

All the other measurements for these two bikes are exactly the same. Exactly. The only difference is the 2 degrees in the headtube angle. The 74.7 is a track bike, and the 72.7 is a "road" purpose fixed gear ... which leads me to suspect that the 72.7 would have more relaxed handling ... my question I guess is will the difference (everything else being equal) be enormous? I have a road bike (a good one) and would like something with snappier handling for riding around the city on ... but, I am likely never ever going to see the inside of a velodrome.

Crap. I guess I'm just going to have to ride some bikes with similar geo. at the LBS. I hate doing that though when I know that I'm not going to buy anything from them.

I had 2 bikes, 1 with 73º HT angle and 1 with 74.5º. I prefer the 73º on the street. The steeper angle was TOO twitchy for my intended use which is long but fast rides.

FWIW, baseline road bike geometry is here because of a huge amount of evolution, refinement and sweat from pro framebuilders and cyclists. The idea that track geometry is more appropriate for city riding is a lot more recent and the people who worry most about it these days seem to be kids on the internet who are still learning about bikes. In the absence of any hands on experience you might want to consider whose word is worth more.

Well yes, there is that.

However, couldn't you say (and I'm gonna) that all the years of effort and work that has resulted in the common standard for road bikes is more appropriate to long rides and variable terrain than say, dodging streetcar tracks and weaving through downtown gridlock? I have a handmade road bike and appreciate the nuances of its craftsmanship when riding it, but it's not the bees knees in city traffic. I have a mountain bike with slicks that I use for city errands and it performs that task an awful lot better than my road bike would. I don't know about such things (obviously) but the geometry on that bike is different from my road bike, no?

Having a road bike and an (un-fun) bike for errands in the city (which is where I live), I'd now like a bike which suited to my urban environment and which is fun (more fun than my errand bike) for toodling around on when I'm not out on a training or group ride on my road bike.

Is a track bike the best suited vehicle for the street? I dunno. I'm certainly going to be running a brake ... but that's sort of the question I am asking here. Given the geometry difference between the two bikes I've mentioned here, is the handling difference going to be huge? (I'm starting to think yes)

As always, the best evidence is to go and ride around, so I'm going to try to do that on some bikes which are similar in geometry to the ones I'm considering buying. I thought that perhaps this question had an easy (easy-ish) answer, but since it seems it doesn't, I'll go do the required legwork to figure it out.

Ta for all the responses.

I agree with Trigger. I think for those of us who would rather sacrifice a little comfort for added acceleration and twitchiness, track geometry makes more sense. Mass market geometry paradigm basically holds that city bikes should be as slack as possible with room for large tires because people want to ride slowly and possibly on the sidewalk. Not all of us ride like that. Traditional road geometry (73 parallel ST/HT, 45mm rake, lower BB, longer chainstays) still 'works' in the city but for a lot of intentions and purposes doesn't shine quite as well as track geometrty (steeper HT, less rake, steeper ST, shorter CS, higher BB). For example, I can take a corner with either BB height but would rather have it higher in the city where I may be turning tighter on a 90 degree corner (and pedaling through it), and lower on the road where the stability of cornering down a 40mph descent (and coasting) is more desirable.