How many of you have gone the opposite of the trend these days and actually sized down on your latest MTB?
Had a conversation with a buddy of mine this week. He said he ordered an Intense and on their recommendation, he went with a medium.
Their (Intense) chart had him on the medium, but he sized down on his next bike to a small and felt much better.
Anyone else done this?
Hump
I’ve played around with sizing as I’m at the upper end of large. I’ve tried xl and medium and liked the xl a lot, but for balance my current bike is a large. Context of model matters though. I have a blur 3 that I upforked to 120 and that shorted the reach fairly substantially. What model intense was his? That definitely has an effect
Sniper
@Andrewbn42 Im on Pivots and their FAQ always ask about what size.
They typically say go by how you want the bike to ride and handle.
I’m know Chris Cocalis has mentioned he usually sizes down because he likes the way the bike handles.
Hump
I basically sized down to get to my current MTBs.
I went from a medium Ripmo to a medium Blur TR. They sound like the same size, but the reach and stack measurements are a few cm different (the Ripmo is bigger).
Have you looked at Lee McCormack’s fitting system? It starts with a measurement called RAD. I’ve found that really useful for MTB because it takes into account how you move the bike around.
On the MTB, you need to lift and drop the front and rear ends to make it over obstacles and down descents. You’re basically levering the bike with your feet on the pedals and your hands on the bars, so what’s most important is that you can use straight arms to lever the bike around the BB.
So you measure the minimum distance between your hands with straight arms and your pedals, and make sure the bike doesn’t put you at a longer distance. RAD is basically the hypotenuse of the triangle created by reach and stack.
My Ripmo was about 3cm too long for RAD, but my Blur is spot on. I’m amazed at the difference - the Blur is the first MTB I’ve felt comfortable jumping and popping.
This is a video that does an ok job of explaining RAD measurements: HOW TO FIT A MOUNTAIN BIKE TO YOUR BODY | Free Fit Kit - YouTube
Lee McCormack’s book “Dialed” has the full set of measurements and explanation.
It’s a little complicated, but I’ve had great results with it over the past year.
+1 for Lee, RAD and SHO. I had ridden my Dad’s Camber and loved it. Got myself an Epic Evo (pretty similar bike) and it didn’t feel nearly as good. Checked the SHO on the Camber and it was very close to zero. Adjusted the Epic Evo SHO to be ~5mm (originally ~40) and got that same awesome feeling as the Camber.
If you use his calculator and YouTube videos ahead of buying a bike you will be so much more likely to get the right thing. Much easier to swap a stem and bars than frames.
Quick tip on SHO and the SQLab 16-degree sweepback bars. A stem length of 60mm gives you basically neutral SHO with those bars. And most of the modern geometry XC and DC bikes come with 60mm stems…
I have read and watched Lees info, and he bases his measurements on a 40mm stem.
Hump
I’ve had a bunch of L bikes that were just too small. XL for me all day long. Downsizing hasn’t worked in bikes and especially hasn’t worked in ski boots. However, I’m not on the cusp.
Joe
Not exactly - at least not in his book or everything else I’ve seen.
When you have a handlebar with typical sweepback (like 9 degrees), starting at the typical part of the bar, a 40mm stem gives you a neutral SHO (steering hands offset - basically where your hands are inline with the bolt that keeps the headset topcap in place.
So he bases a lot of his advice around those typical bar dimensions, which results in a 40mm stem. But throughout the book, he references multiple stem lengths.
I remember hearing it on the Joy Of Bikes videos he does.
Hump
I’ve never seen where he talks about setting a bike up for XC racing. Mostly for trail riding.
Hump
That’s just an example. He really advocates calculating / measuring SHO and doing whatever it takes to get that as close to zero as you can, using whatever stem and bars are needed.
Basically, most bikes have gone to long reach with short stems, stems which are already close to the limit of how short you can go. This means that if you used to fit a large but would often swap out to a shorter stem, you probably need a medium on newer bikes, since you might only be able to get a stem that’s 10 mm shorter than the stock short stem on a new bike. Whereas before, the bikes came with longer stems so it was easy to shorten the reach more with a stem swap.
That’s why the advice is to consider a size smaller IF you are close to being in between sizes. It’s so much easier and cheaper to put a longer stem on than to find out you need a shorter frame and resell the bike / frame. However, not everyone needs to go down a size.
For example, I am 6’ 1” with typical proportions of torso length to leg length. I have always ridden a large bike. According to Specialize’s size chart I am on the border of fitting a Large or XL frame. I bought the large. When I looked at what I needed to do to get to a zero SHO, I had to go to a super short stem or else I would have needed tons of back sweep, which I didn’t want. If I had gone with an XL frame, I might not have been able to reach zero SHO, plus I would have a heavier, harder to handle bike.
I ride an Intense Sniper. At 6’2"/188 cm I bought an XL per their size chart and the LBS recommendation. The fit is totally adequate (and it’s a great bike), but I’d get an L if I were to purchase one again.
Not the best article but it does present some sizing issues.
A couple of mtb’s ago I sized up to a ML in a Bird Aeris 145LT - this was in the company’s recommendation. I’m 5’9 and the reach was 481mm - so much longer than most other equivalent bikes at the time (2017). Bird aren’t far off Pole / Geometron sizing.
I found this too long - mostly in terms of weighting the front wheel on fast and flat corners - I had a few crashes where I washed out the front. Input this down to having relatively long legs but quite the a short torso and arms vs the average. I ride with a guy who now has the exact same size and model of bike and is 5’7 but he’s comfortable on it - I think he’s more short of legs / longer of torso and arms.
When I swapped the frame out for a Bird Aether 7 I swapped down to a M based on my experience and just found a lot more confidence on it - and despite being shorter travel / shorter chainstays I was faster on it almost everywhere. The only place I lost time / speed was on hefty uplift day style trails with long straight and rocky trails. E.g Antur Stiniog. Reach on the M was 457mm or something like that.
I’m now on a Transition Sentinel M - so 451mm reach and I love the thing.
If I were designing my own full suspension geometry I think something like 465mm would be perfect - but not many bike companies have a frame around that size. M is 450 ish and either ML or L is around 475-490.
After some experimenting last weekend, I reaffirmed my preference for large mostly. I demoed the pivot 429 trail in large and xl and the xl just didn’t feel balanced around corners. It really felt like I was chasing the front wheel and struggling in tight sections. What I’ve found is it really comes down to reach and wheelbase balance though. I’ve tried many bikes in large and xl and even back to back of the same model. I have preferred larges in almost all cases except for the smaller reach xl bikes like the Hightower LT and sb5.5. Both of these bikes had about 465 reach, so in line with many larges. The other important thing I’ve found is front to rear balance. The two xl bikes I liked had chainstays around 440, and the ones that have felt unbalanced were 430. 430 works for a shorter bike for me (blur 3 TR) but with a longer bike it seems unbalanced. I’ve also never found a bike with more than a 1220 mm wheelbase that felt like it turned in a Balanced manner.
This is all coming from someone with an xc/trail background and is all arms and legs, so my natural center of balance is further back on a bike. I don’t like forcing a position that is too forward because it means that to make the bike work I can’t be in a relaxed position with light hands and I lose some of the flow which is where the fun and speed really come from. For reference I am 6 feet and change tall, with and inseam of 35,5in and 6’ 4.5 wingspan, which means I’m almost at the break point of many sizes, but have proportions that fall well outside the norm
I can’t seem to get away from sizing my bikes based on seated power pedaling position, considering it’s where I spend 90% of my ride time. This has me questioning that, but I think it always comes back to making compromises based on the bike and your own goals. Geometry charts and recommending sizing (based only on height) seem to exist only to confuse riders at this point.
@ibaldwin That’s normally my number one priority. I feel I can adapt other ways, but I don’t want to give up swayed climbing power and speed.
Hump
I sized down with my last full susp from a large to a med. but very dependent on bike/brand. I’ve had a string of Santa Cruz tall boys, High ball and one other and tried to get into a SC med but they were always too small mostly seat tube and stack. I’m 5’10 but long 32/33" inseam…and i’m a masters and shrinking! It happens especially with cyclists…get ready…it sucks.
I just switched to a med. yeti SB 100 and it fits but barely. I am on the hunt for a 115 and open to a large. No real story or advise here but overall the switch to a smaller bike was pretty predictable in its performance (you could throw it around better, get over the wheels better for traction etc) and pretty much for the better except on fast fireroad descents it feels a bit squirrely and curtain cadences of rough flow it’d be nice to have something bigger.