Why Proper Bike Size Is Important

I talk about how Reach and the controversial RAD (Rider Area Distance) measurements affect how much control you have over your bike.
RAD is a guideline to help you determine how much leverage you have over the pitch control of the bike.
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[@painterabc123]

Nice work on the double. I have lots of room for improvement on my jumping. 8:46

[@sadiejones7991]

Great explanation

[@twowheelsforlife]

That wood jump in slaughter is mint! You live in bentonville? Bikefest this weekend and hope rain holds out!

[@ShadLife]

I do not live there, but I visit there regularly. On my way down today for the Bike Fest.

[@twowheelsforlife]

@ShadLife my son, bro-on-law and myself will be there sat and sun.

[@mattdesmondwashere]

So I'm a medium at 5'7" by pretty much all bike company fit standards. The RAD measurement says they are all wrong? I ride a size small beargrease with a 404 reach, but also a Medium YT Izzo with a 150 listed reach. They don't feel all that different. The distance from the seatpost to the bars is nearly identical the way I have them set up with factory stems. Just trying to find out if I should try a size small for my next full-sus bike. Many brands I'm interested in are not able to be test ridden because they are factory direct, so this makes choosing a size very difficult.

[@ShadLife]

RAD doesn't come into play while seated. The effective top tube is different from Reach which is the measurement you want to factor in while standing. Both reach and RAD are based on the center of the bottom bracket, not where the seat is positioned. This is likely why the bikes feel similar while seated and pedalling. One thing more modern full suspension bikes are doing is having a much steeper effective seat tube angle. This reduces the effective top tube, but it doesn't change the reach. They do this because modern trail and enduro bikes have a longer reach measurement so they steepen the seat tube so your seated position still feels normal. Whether you want a shorter full suspension bike or not is personal preference. If it's harder to pull up the front end while standing and riding tech and you would like that effort to be less, a shorter front end will allow for you to have more arm leverage and use less effort to get the front end up. A shorter reach can make a bike easier to move around, what I call pitch control. At the extreme end of this would be a BMX bike. I am also 5' 7" and for me personally, 450mm would be way too much reach. Like I said in the video, I am pushing it at 435mm with the Spectral 125 in size small. This bike is slightly RAD+ for me. My previous bike had a 420mm reach and I really felt comfortable on that frame. I am however getting used to the 435mm reach and I am finding its advantages when at higher speeds and hitting bigger jumps and such.

[@mattdesmondwashere]

@@ShadLife That is a good explanation, and totally describes why it's tough for me to manual the Izzo. I have short legs and normal torso, so bike fit is difficult for me to get right. I guess the trick will be to find a bike with similar measurements to what I'm looking for and test ride that before buying a DTC brand bike. Thanks!

[@rickysolis8291]

What’s a good entry full suspension mountain bike? Thanks?

[@ShadLife]

That's a tough question to answer here because there are so many of them. A good rule of thumb is that for a full suspension bike the good entry level ones start at around $2500 retail and go up from there. There might be sales with less expensive prices, but look at the retail price to see what the discount is. Don't buy from a department store or big box (like Dick's) type store. A few legitimate brands are Trek, Specialized, Giant, Canyon, YT, Cannondale, Rocky Mountain, NORCO, Kona, Haro, and many other brands I didn't mention.

[@rickysolis8291]

@@ShadLifeMany a lot of brands to choose from but I don’t know what brand to buy? What’s good for beginner like trail or enduro bike? Is your bike good for beginner or someone advanced? Thanks….

[@ShadLife]

@@rickysolis8291 My bike would be fine for any skill level. It's usually that beginners don't generally want to spend a lot of money on a bike until they know if they are going to like the sport. So basically I was suggesting a starting baseline and then go up from there. Almost all brands sell a wide variety of price ranges starting from entry level $2500 (retail) full suspension bikes and then go up from there. So there isn't one particular brand that is better for beginners. I think if you want a good bike brand so you can get a feel for the sport, a Giant Trance would be a good place to start. They make entry, mid, and higher end Trance's.

[@rickysolis8291]

@@ShadLifegood to know, thanks for your input. Like your videos!

[@markus4023]

I just bought an XL Ripley and I think I’m wishing I bought a Large. But I’m not even sure bc I never rode the Large. Sizing chart said I was between sizes

[@hammertime7740]

Ripley sizing runs small. Im slightly cramped seated, but it feels perfect with the dropper down. They overcooked the steeper seat tube angle.

[@houseofhorror]

Did you say what size frame your bike is?

[@ShadLife]

No, I only mentioned the amount of reach it has. It's a size small.

[@oliwierrr]

RAD from "Joy of Bike" channel is the best method for me:D

[@ShadLife]

RAD is essentially measuring your leverage ability over the bike. It's definitely one measurement to consider when buying a bike.

[@oliwierrr]

@@ShadLife I have M size with 50mm stem and it's perfect but I'm wondering if L size frame with shorter stem like 35mm would be better with new bike

[@ShadLife]

The longer frame size will give a longer front center. So if you do a lot of downhill and higher speed riding I suggest trying that. If it's mostly tight twisty singletrack your current setup is probably fine.

[@oliwierrr]

@@ShadLife I'll try longer frame, thanks:)

[@zap...]

That's what she said.

[@ShadLife]

What grade are you in? 🤦‍♂️

[@godstrashman]

The RAD thing is outdated at best and at worst, baseless and misleading for newbies about to drop a lot of money on a bike. What a coincidence that the guy selling a book and consultations on bike fit has discovered the sacred geometry that eludes every single frame designer today.. I tend to size down slightly from super-progressive geo myself but if the goal is the become less of a 'passenger' the absolute worst thing to do is get a bike that's too small and encourages hanging off the back of it

[@stevematthes4325]

The guys at "Joy of Bike" explain this a little bit better.

[@ShadLife]

Alex isn't really doing Joy of Bike anymore, but I agree, they talked about it quite a bit back then and did a good job of it.