Make your bike match your body
The bike setup section of this site contains all the details you need. Briefly:
Put your saddle wherever you need for comfortable pedaling. Here are some tips.
When it comes to shredding — generating peak torque and having complete control of your bike — the most important relationship is the one between your hands and feet. Unlike the classic fit methodologies, the RideLogic™ system positions your handlebars independently from your saddle. Independently.
When you jump well, you actively manage the lever between your hands and feet. The more closely that lever matches your body, the better you can jump.
Get RAD. The Rider Area Distance (RAD) is the imaginary line between your bottom bracket and the centers of your grips. Basically, your ideal RAD lets you achieve full hip extension with your shoulders packed and arms perfectly straight. This is just like a deadlift. It allows you to access your full potential strength, and it gives you great range of motion for turning, braking, steeps, etc. Read more about RAD.
Rider Area Distance (RAD)
Then get RAAD. The Rider Area Angle in Degrees (RAAD) is the angle of your RAD compared with level. The more XC/road your bike is, the lower the RAAD. The more downhill/motocross your bike is, the higher the RAAD. Read more about RAAD.
Rider Area Angle in Degrees (RAAD)
If your bike is the correct size and your RAD is dialed, your RAAD will be fine, and your bike will feel great.
Find your ideal handlebar width. Your ideal handlebar width fits your body — not the kind of bike you ride or the decade in which you’re riding. It provides a good balance of pulling and pushing strength. It gives you plenty of arm range for bike handling. It helps you do the big work with the big muscles in your torso, rather than the small muscles in your shoulders. And it helps you get more decades out of your shoulders. Calculate your ideal handlebar width here.
Hi!
I want to share my observations and finds from numerous experiments on 4 bicycles I have atm and even more autocad drawings of bikes + stems & handlebars combinations and positions which I had to do since just working simple math for reach and RAD lengths does not work by itself and is only a starting point for creating perfect fit. What is proposed (using RAD & RAAD to size bike & fit) is not wrong it actually profoundly correct but getting the correct RAD and RAAD values for each person is a lot harder than what has been suggested imo. Please let me explain:
RAD length gives you infinite positions since this value is nothing more than a radius of a circle with center in the bottom bracket and that circle has infinite positions. Now you can and should narrow it down to a point or small range by either calculating the reach value as suggested or using RAAD angle as described and this is again good enough starting point. Here are main problems:
– measuring RAD will give you range of results depending on how you measure
– calculating reach by multiplying height with 2.5 as suggested is wrong because it does not take in to the account arm, torso, neck and head lengths and 10mm difference in result variation is a lot when you test it on the bike
– Both RAD and RAAD do not consider weight distribution over the front and read wheel when cornering flat turns since this is greatly affected by head angle and chain stay length and reach/stack height have to compensate for it
– seated position is just another wild card that needs to fit as well as previously stated front/rear wheel balance
I found that I measured RAD so many times and results would be different each time and that in it self would not be a problem but if your reach is wrong as well, than yes your fit is off by miles even so much that every bike length jump sends you over the handlebars, or you fight with lack of traction over front or ear wheel when cornering flat or offcamber turns.
To solve these problems I would recommend using method in this video:
https://www.youtube.com/watch?v=HyppZOpHocM
to check RAD length and maybe use autocad or this webpage:
https://madscientistmtb.com/bike-geometry-compare/
to check all possible combinations of reach and stack you can have on your bike for your RAD length, this is needed to adjust reach and stack length to suit bike geometry/balance without changing desired RAD length.
Thank you Nikola.
1. A person must measure their RAD correctly. This site has tips for that. When I do fit consultations, I ask people for videos of them checking their RADs. Mistakes are common, but there are ways to get consistent numbers. The Joy of Bike video is not a great method; using one hand makes it way easier to mis-measure. Here is a good way:
https://www.llbmtb.com/members/bike-setup/measure-rad/
NOTE: If a rider cannot achieve a consistent RAD measurement, they are not consistent with their body mechanics. This makes any athletic skill hard to master. In the case of hardcore MTB, this increases risk of injury.
2. Regarding fore-aft weight distribution, see the Cornering 3.0 section of this site.
https://www.llbmtb.com/members/riding-skills/cornering-3-0/
3. For seated position see the Magic Triangle calculator on this site.
https://www.llbmtb.com/members/bike-setup/magic-triangle/
4. The calculator you linked to is missing handlebar setback. You cannot calculate your setup accurately without that number. I see how they are trying to calculate setback, but that method doesn’t account for the wide variety in bar shape. The most precise method to calculate RAD, RAD Angle (aka RAAD) and SHO the bike calculator on this site. You can either measure your bar’s setback or use the charts on this site for known bars.
https://www.llbmtb.com/members/bike-setup/rider-and-bike-calculator/
No matter whose calculator you use, it pays to dial in the final details with the on-bike check. You must have a consistent body RAD.
https://www.llbmtb.com/members/bike-setup/ridelogic-bike-setup-on-bike-check/
5. Every multiplier is a starting point based on average proportions and needs. This is a great way to help most people in a simple way, which is all most people need and can handle. The A1 best way to get your fit perfectly dialed is by working with me directly. I take all of the variables into account.
https://www.llbmtb.com/product-category/bike-setup/
I hope this is helpful,
Lee
Hi,
I am slightly confused. I am 5′ 7.5″ and my RAD is 766mm. I have a 2019 Cube Stereo 150 in small. Cube states that I should be well within riding a medium size, however even on a small with a low and short stem the a RAD of 805mm which is RAD ++. I am not to unusual in shape or size, the bike doesn’t have progressive geometry and isn’t particularly long, so why should this be so far out? I would hate to think if I bought a new bike with progressive geometry – I would be on an XXS!
Hi Steve,
From here it’s all math. If you want to ride with dynamic integration with your bike, you need the bike to be RAD neutral or slightly RAD minus compared with your body. We can run numbers that tell us what frame reach you need. From there we choose the frame size, then we model the details using the RideLogic bike calculator on this site.
https://www.llbmtb.com/members/bike-setup/rider-and-bike-calculator/
The bike industry sizing is way out of whack these days. This is because they are all chasing this “longer is better” trend. It’s a trend, and every company who wants to sell bikes has to follow it. A classic example is Chris Cocalis, founder of Pivot. He’s a smart engineer who fought the trend, but the man has to pay his staff and feed his family, so he made his bikes longer. But get this: I heard him say he, his racers, his staff and the people they fit at demos have all gone down a size. Yeah.
Here’s a great example: The reach on a small 2023 Santa Cruz Nomad is LONGER than the reach on a 2013 XL Santa Crux Nomad. That means if the 2013 XL felt good to you, you need a size S in the 2023 model. I made an infographic! It is here:
https://www.llbmtb.com/wp-content/uploads/2023/06/santacruznomad2013v2023-1.png
This requires people, especially men, to get over that size letter. An S doesn’t make you less of a man than an M. Hopefully you’re not stuck in that trap, but many men are — which is why I’m talking about it here.
I am exactly 5’8.5″ tall per my doctor. I’m ridden mediums for 35 years. My most recent bike, an Ibis Exie, is a size small (and I still feel like a man). Many modern bike are too long for me in every size. I’m fortunate to be offered bikes from various companies. I look at the geo charts. If the reach on the smallest size is too long for me, which happens most of the time, I say thank you but no. It’s a total waste of time to ride a bike that doesn’t allow me to ride my best.
Based on the numbers you gave me, the MAXIMUM viable frame reach for you is about 411 to 425 mm. It’s best to err shorter, especially if you want to ride technical trails well. Your small with a reach of 420 is a hair long but workable (only with specific stem and bars; use the calculator on this site; plug in a 30mm stem with zero rise, a SQlab 30x 16-degree low rise bar upside down with -15mm of rise, and 25mm of half stack (that’s 5mm of spacers under the stem)). If you hire me to do a 1:1 fit for you, I’ll push you to the XS with a reach of 405mm. The medium with a reach of 440 would be very disappointing.
I’d love to say trust the geo charts and the local bike shop bros who memorize them, but that just won’t give you a great-fitting bike. My biggest advice for all men is to get over yourself when it comes to your height and bike size, run the numbers, make an informed buying decision, focus on your abilities then spread joy everywhere you ride.
Does this help?
Lee
Hi Lee! thanks for so much your content. And writing style =). I just got pointed RAD / RAAD, and it throws me off my current dream bike Orbea Occam M10 oder LT, which i intend to buy. If RAD wasn’t 58 mm too big, it seems. And RAAD 56,7° would be rather XC according to you?
Now the Occam seems such a nice allround bike from what i read, here for example:
https://blisterreview.com/gear-reviews/2022-orbea-occam-occam-lt
So i’m quite confused. Also, i hear many pros say, when i doubt, take the larger frame.
Maybe you can see an error i made with the numbers? Or are bikes nowadays so different?
I am 187cm tall. That would be 836 RAD.
The Occam XL (the dealer wont even sell me an L) has 895!
Stem 40mm, Handelbar: 20mm rise, 8 backsweep, 5 upsweep. 3 Spacers i guess 15mm, (not sure about the stem height on bikestats though).
Configured it here (unfortunaltely the link does not save the above numbers ) https://bike-stats.de/en/geometrie_vergleich?Bike1=Orbea_Occam%20LT_2022_XL&Bike2=Propain_Hugene%20CF%2029_2022_L
now the only number I’m not sure of, is the “headstack height top”, that would make things even worse…
Tanks Lee!
Wilf
Hi Wilf,
If you want a great bike fit for dynamic mountain biking:
1) Measure your body RAD. Make sure you get an accurate number, then save that number. You’re right: If you have average proportions your RAD is about 836mm.
2) Use the bike calculator on this site to model the details of your bike. Strive for a perfect RAD and and RAD Angle (formerly called RAAD) around 58-60 degrees for technical riding. The numbers do not lie. Ignore all letter sizes (S, M, L, XL); they are meaningless. Assuming you have average proportions I suggest looking at bikes with frame reaches from about 450 to 468mm. The shorter ones will feel better in technical terrain. Don’t be surprised if you end up on a medium.
https://www.llbmtb.com/members/bike-setup/rider-and-bike-calculator/
3) Buy whichever bike fits you according to the calculator. DO NOT let some guys at a bike shop tell what you can and can’t buy. Their false pride often matches the level of their ignorance. You are the customer, and you are armed with knowledge!!
If you need help, you can do a 1:1 consultation with me:
https://www.llbmtb.com/product/bike-selection/
I hope this helps,
Lee
My RAD is around 83cm-84cm and my bike with a new 45mm stem installed recently and with all the spacers used at max (3.5mm top cap gap distance) is roughly around 82cm and I feel like when steering with the bars a little more than usual (mostly on difficult climbs) I’m slightly touching my knees on the bars (I think the shifter levers in particular)…I have a spare 60mm stem around and I was thinking installing that and see how it goes, but still I like it a lot how my bike handles with the newly installed 45mm stem than with the previous 60mm that I had on…so I’m still a bit unsure on weather going back to the 60mm stem or stick to my 45mm, but dealing with the knees touching the bars at times…so what you reckon?? Any other advice maybe or suggestions?? Thanks!!
Hi!
If your knees touch the bars when you’re pedaling out of the saddle, that’s likely an issue with your form. Try pushing your hips back and pedaling from a hinge rather than a squat.Your quads won’t burn, and you’ll have more power.
The best way for you to add RAD to that bike, while retaining that nice short-stem, short-SHO feel, is to increase the rise of the handlebars.
Namastoke,
Lee