Bill1

I am getting into road biking on a budget and considering two used bikes. One is a 58cm traditional frame which may be a little small and the other is a 61cm compact frame that may be a little large. I am 6'2" with a 90cm biking inseam. I think they would both work for me with some adjustments, but in general is it better to get a smaller bike and adjust up for reach, etc., or get a larger bike and adjust down? Any help or advice would be appreciated.

John E

I generally prefer a cm or two too small over the same amount too large, but note that the top tube length is arguably more important than the seat tube length in determining how well you can fit a given frame.

Bill1

Good point John E. The eff top tube lengths are 57.3cm for the 58cm and 60.6cm for the 61cm compact. Can the stem be changed to make up the difference between these two?

europa

You face two issues - the first is reach and the second is handle bar height. In this brave new world with threadless head sets, these can only be adjusted by buying new parts. If you're looking at getting the bars up at saddle height, you're in for a real fight if the headset is too low ... this is why I ride such large frames.

The other issue that has been pushed over the years is stand over height. Mate, that's utterly irrelevant. Both my main bikes (traditional flat top tubes) touch my groin when standing over them and neither has ever given me a problem (I've been riding one of them since the 80's). However, the bike I bought that was sized by a professional bike fitter, requires head stem extenders to lift the bars high enough and, strangely enough, a shorter neck than standard.

So go back to your bikes and see which one you can comfy on as far as handle bar position goes - that's AFTER you've adjusted the saddle properly fore and aft. Your decision will depend on what parts you need to buy and if they're actually available (don't assume they will be - experience speaking again).

If you're really lucky, both will fit and you'll be able to buy the one you really like, which is an important consideration too.

Richard

BikeWNC

Both guys above pretty much touch the important points. Effective TT length will also differ if the ST angles are different. Do you know the geometry of the two frames? Unless you are grossly misshaped, which at 6-2" and a 90cm bike inseam you are not, either frame may work for you. As mentioned, the head tube length will likely be the determining factor here. Chances are you will not want the bars 10cm below your saddle so compare the two HT and see how they work for you.

Post the frame geometries and let's have a look. BTW, I'm just under 6'3 with the same inseam and ride a 58.5cm TT. My other bike has a 60cm TT. Both are comfortable.

Bill1

BikeWNC - here are the geometry numbers for each frame:

58cm Horizontal Top Tube
Head Tube Angle 73°
Seat Angle 73.5°
Top Tube 56.9
Eff Top Tube (ctr-ctr) 57.3
Chain Stay 41.7
Fork Offset 4.5
Wheel Base (ctr-ctr) 100.4
Stand Over Height 80.8
Seat Tube (ctr-top) 58
Head Tube 14.3

61cm Compact
Head Tube Angle 74°
Seat Angle 72°
Top Tube 56.9
Eff Top Tube (ctr-ctr) 60.6
Chain Stay 41.1
Fork Offset 4.5
Wheel Base (ctr-ctr) 101.1
Stand Over Height 81.5
Seat Tube (ctr-ctr) 53.8
Head Tube 19.25

BikeWNC

First, at your height, 1º of STA will equal 1.3cm in TT length. So the smaller frame with the 73.5º STA will have a comparative TT of 59.25cm to the larger frame's 60.6.

The item that stands out the most though is the HT length of the smaller frame. 14.3cm is pretty short. I assume it has a standard headset which adds 32mm to the total. Still the larger frame with a HT length of 19.25cm is way longer even without adding the headset whether internal or standard.

So with the HT length of the smaller frame being what it is, I would say that frame would not work for you. It's just too short. Do you know how much saddle to bar drop you have now on your current bike?

I could ride the 61 frame. I would probably use a 120 or maybe a 110 stem with it but then I'm used to being stretched out. The thing that concerns me about the geometry is the use of a 4.5cm fork rake with a 74º HTA. That makes for a low trail and usually the rake used on a HTA of 74º is either 4.0 or 4.3cm. The 4.5 may create some handling issues.

BluesDawg

For your size, I would think the 58 would be too small. Those numbers are pretty close to what I ride at 6'0" and 87mm biking inseam (PBH). You could probably make it fit with a long stem and seatpost, but better to get something that fits well without going too far outside the normal range of fit.

Number crunching and theorizing is OK if you have no choice, but there is nothing like a test ride to tell if a bike fits or not.

europa

They're both 'used' so take them both for a decent ride. Buy the one that works. If neither does, look further. I a seller doesn't want to let you ride it, and you need to offer some sort of reassurance/security that you're not going to keep going, don't buy the bike.

The ride will answer two things - firstly the fit and probably more importantly, how the bike itself works. You may not like the way it handles. You may notice that the wheels don't work at high speed or maybe the gears are rubbish. There's nothing wrong with buying a bike that's worn - provided it was maintained, a bike only gets worn by being good to ride, it's the shockers that get left in the shed. But you do need to consider the cost of doing it up - new cables, brake pads, tyres, chain and cassette might sound like a lot but if the frame, wheels and fit are good, you're laughing.

Best of luck with it. We're only guessing. Only you can answer the size issue and you can only do that on the road. Sorry, no easy answers to this one and it pays to get the right answers before you pay for it.

Richard

Bill1

Thanks all - the information and advice were excellent. I have ridden both bikes, but just for a few minutes each. They were both in very good condition shifted well and appeared well maintained. Based on your feedback and other info from searching the forum archives, I believe the larger frame is the way to go. I will take both for a longer ride this weekend and hopefully one will follow me home and my wife will let me keep it.

europa

Don't let it widdle on the sofa

Richard

seriously, when you lean it against the sofa, make sure the chainrings are on the outside - guess how I know this