Ideal standover height and top tube length?
I have two questions about proper bike fit that, unfortunately, the first chapter of your book did not cover: (1) how important is standover height?; and (2) how do you determine the proper top-tube length?
Here’s some context. I am 5’10”, but only have a 30″ inseam. The bike I am currently riding, a Gary Fisher Piranha (Medium, 17.5″), has a standover height of 29″ and an effective top-tube length of 23.9″.
One of the bikes I am seriously considering is the Santa Cruz Blur LT. I really like this bike, the only problem is that I wonder whether it really fits me correctly. It has an effective top tube length of only 22.5″ and the standover is 30.2″. The tall standover height seems like somewhat of a problem, though my local bike shop assures me that’s not the case. And I get their point – bikes with lower standover height generally have a more dramatic slope to the top tube, so any fall with forward momentum is going to put me over the bike in a place where the standover height is greater than my inseam anyway. Also, I have heard from multiple sources that the most important measurement for proper bike fit is the top-tube length, but how do I know if 22.5″ is right for me for this type of bike?
$3,000 is a lot of money to spend on a bike, I just want to make sure I get one that I will be happy with for the foreseeable future.
Thanks for your help.
Corner by Lee. Vector graphics by Lee. P.3 frame by Specialized.
Great questions. You seem to have a relatively long torso and short legs. Based on that, you’ll want a bike with decent standover clearance and a pretty long reach.
That’s always been the gold standard of bike fit, but not so much anymore. With suspension and high bottom brackets and all that, few of us can straddle our top tubes with the few inches of clearance our forefathers demanded.
BUT: More clearance is better. Not only for straddle-safety, but also for cornering. A lower top tube lets you lean your bike more. See the diagram action madness.
Top tube length
Your ideal top tube length depends on your body, the terrain and your riding style. XC riders want mega reach; dirt jumpers need mini reach. There is no set way to determine this. Not yet, anyway — I have an idea for an all-new sizing system, but that’s pretty low on the list.
In the mean time, measure the reach on your current bike. That is, your effective top tube length plus your stem length. For example:
I’m 5-9 with average leg/torso length. My medium Enduro has a 23″ TT and a 50mm stem with a total reach of 63.5cm. That feels a bit short for climbing, but perfect for descending.
Gary Fishers have very long top tubes and short stems. Gary calls it “Genesis Geometry.” I too prefer a longish top tube and a short stem. Even with the same overall reach, short stems handle better than long ones.
Your reach seems a bit long to me, but if you like it, start there. The Blur’s top tube is about average.
That’s a pretty long stem; I think you’ll prefer a 90 or even a 70, but that’s a matter of riding style.
At 5-10 with a long torso, you’re between a medium and large. Many bikes get longer but not taller. You might consider a longer frame and a shorter stem. Test ride bikes at your local shop, and buy your bike there.
I want to give you a set rule, but I don’t have it (yet). I hope this helps,
Thanks Lee. I have been to about 5 different local bike shops and none of them were able to explain proper bike fit in a way that is as helpful as this. I think you are right that I will enjoy a slightly shorter overall reach, especially on the descents. This gives me a great place to start and some knowledge about how to experiment with the reach a little. Good stuff.
Unfortunately, this advice may mean that I should detach myself from the Blur LT in order to get a little more standover height. It’s amazing how emotionally attached I have become to a bike that I have spent very little time on – damn marketing people. Still, I finally found a shop that will let me demo one in the dirt next weekend. It’ll be good times regardless!
Right on Todd.
Those damn marketing people — when I start *needing* the item I’m writing about, that’s when I know I’m on target.
I just wrote about the new BMW G 650 XMoto supermoto bike … yummy!
Lee touched on it, but for added clarification the standover and bb height will almost always be taller on a suspension bike as the travel increases.
You need room for the suspension to compress without driving your feet into the ground.
When you are actually on the bike, the relative distance between the top tube and the pedals is what matters for “fit”… that is untill you bail onto your top tube.
Crap, now I need a supermoto bike. That looks too fun!
You could try a Blur 4X, it has a longer toptube and better standover. It would also be a serious ripper! If you really want a Blur, then it’s worth checking out. You may also want to try a Titus Motolite. It has great standover and is also seriosly shred-nastic. Or even a Turner Spot, like me, my favorite 5″ trailbike. It takes the cake in versatility and slick like a KY Jelly rassler.
Itâ€™s always about the right sizeâ€¦big issue. Iâ€™m one of those persons who wonâ€™t really fit into the regular sizing sytem of most bike companies as well. Here in Germany the focus shifts more and more on the top-tube length when it comes to the rigth frame size. Especially one company does so (Check the web for Liteville.de). They most of all extend the top-tube when going up with the frame size keeping a low seat-tube length to favour agility and â€šplayfulâ€™ riding . The frame comes with an extra-long 480mm seat-tube with a huge 34.9mm diameter featuring sufficient stiffness beneath yout b â€“ u â€“ t â€“ t. And, the reviews absolutely support their engineering idea. This concept definitely is worth a closer look and a real chance to please people with a somewhat longer upper part of the body â€“ or reach, however you may name it. I was close to buying one myself, but then the ENDURO SL appeared and crossed my plans – but if SPECIALIZED keeps on taxing my patience I may get back to the LITEVILLE 301.
By the way Lee, although you might have read that a few times already, now also from me: Great website, both thumbs straight up!
Greetings from Germany
I think the next one I’ll look at is the Titus. It seems to have the best standover and I have heard it rips. I really like the Turner too, but it has the highest standover of them all (for size M anyway).
The difference in the large and Med (BLT)is 1/8″ but a inch in top tube. It might be worth rockin the large. The 4x would be worth looking at as well and its only a 1/8 less in standover but shorter in seat tube and bottom bracket and just plain rails corners. I love my large BLT and had a med fisher for a play bike and the reach is very simular.