New bike geometries and sizing

phillychris498

Well-Known Member
Some of you may remember that I built up a new-fangled, model year trail bike this summer (and cracked it very quickly, but that’s another story). I was really excited for the bike, and while I knew going in that companies like Santa Cruz were making bikes longer, lower and slacker, I didn’t take this into account when I was building up the bike.

Fast forward 400 miles later and I’m thinking that I should’ve actually sized down from the large I used to ride to a medium for a new style geometry bike. I’m 5’11”, and my old large bike was shorter travel, steeper, and shorter in terms of both reach and wheelbase. I tried out the large in my new model bike before buying the frame, and noticed the differences immediately but was hesitant to size down to a medium since I’ve ridden large since I was 15. At this point, however, I’m struggling to ride technical up features as well as I did with my old frame, and struggling generally with maneuvering the rear end of the bike. This might be further exaggerated by slightly lower fitness/an issue I’ve been battling with neck/back tightness, but I’m starting to think I’m really a medium in newer geometry bikes.

have any of you all downsized on a new longer reach/wheelbase bike and had success? For reference, here are the geometry differences of my old frame vs current frame:
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Ryan.P

Well-Known Member
Team MTBNJ Halter's
Your on the correct size bike . What size stem / bar are you running . Vpp bikes are a lil tricky to get the suspension doing what you want
 

Jmann

Well-Known Member
I’ve actually been sizing up. I’ve learned I really like a long reach on my bikes. I’m 6 feet without a long torso but prefer a 480ish reach. I rented a Hightower out west in both large and xl and preferred the xl. I think it has something to do with home much seatpost I run, the longer reach balances it out better. More comfortable for climbing. I also climb out of the saddle a lot.

Which shows how personal bike fit is. On paper none of that makes sense.
 

phillychris498

Well-Known Member
Your on the correct size bike . What size stem / bar are you running . Vpp bikes are a lil tricky to get the suspension doing what you want
I’ve got a 35 mm stem and around 770 mm bars. Rear suspension feels good, front suspension has been tricky for me to dial in.
 

Captain Brainstorm

Well-Known Member
In what world is 457mm considered short? Go by your gut, if the bike feels long and unwieldy, it’s probably because it is. Sounds like around 460 is your sweet spot. That said, I would also use the total wheelbase as a critical measure as well.
 

jackx

Well-Known Member
I have a 2011 Epic Comp 29er and I am in the market for a new 29er. I've demoed a number of newer geometry models in size Large. Even with the slacker geometry, some felt more cramped than others.

Also on some of the newer bikes, when going uphill it sort of feels like the front wheel is about to lift off the ground, but I think that is partially because my Epic had a 100mm stem and so my hands were some 60 cm more forward over the front wheel (than on the new geo bikes). I imagine fork offset may be another factor.

I think if I went with a Medium on a new geo trail bike, I would definitely need a longer stem, but I am not sure how the newer geometry would be with a 100mm stem.
 

Jmann

Well-Known Member
I have a 2011 Epic Comp 29er and I am in the market for a new 29er. I've demoed a number of newer geometry models in size Large. Even with the slacker geometry, some felt more cramped than others.

Also on some of the newer bikes, when going uphill it sort of feels like the front wheel is about to lift off the ground, but I think that is partially because my Epic had a 100mm stem and so my hands were some 60 cm more forward over the front wheel (than on the new geo bikes). I imagine fork offset may be another factor.

I think if I went with a Medium on a new geo trail bike, I would definitely need a longer stem, but I am not sure how the newer geometry would be with a 100mm stem.
I have a same year stumpjumper, and although it’s basically my gravel bike these days, I still like the fit. Have your demo’d 2020 bikes? Most brands have switched to steeper seat angles which helped me get more forward and balanced. The previous generation of geo with newer slacker head angles but with the same slack seat angles didn’t work for me at all. I could never get my weight forward enough to combat the climbing wheelie feeling.
 

jackx

Well-Known Member
I have a same year stumpjumper, and although it’s basically my gravel bike these days, I still like the fit. Have your demo’d 2020 bikes? Most brands have switched to steeper seat angles which helped me get more forward and balanced. The previous generation of geo with newer slacker head angles but with the same slack seat angles didn’t work for me at all. I could never get my weight forward enough to combat the climbing wheelie feeling.
Yes, I've demoed a number of brands and models some 2019 or "current" per Pivot, and some 2020 models.

Although some geometries look very similar, I found that the different bikes feel/ride significantly different. So I definitely recommend demoing as many models and sizes possible.
 

Ian F

Well-Known Member
Odd... with "new school" geometry, I have found myself wanting larger bikes than I used to buy. My Megatower is the first size Large I've ever intentionally bought and it fits me perfectly at 5'-10". I recently ordered a Spot Ryve 115 29, also in large. My current Primer is a medium and it doesn't feel terribly small, but I wouldn't mind if it was a bit longer.
 

Ryan.P

Well-Known Member
Team MTBNJ Halter's
What's the reasoning here? Not doubting you just curious.
No weight on the frontend = no traction = no confidence . Something about your hands and front wheel following the same arch when turning the bars just feels good .I've also tried many size stems over the years and always come back to around 50 or 60 mm it just feels right
 

Mathers

Well-Known Member
No weight on the frontend = no traction = no confidence . Something about your hands and front wheel following the same arch when turning the bars just feels good .I've also tried many size stems over the years and always come back to around 50 or 60 mm it just feels right
I was considering going from a 60 to 50 but was concerned it would hurt the climbing too much. THanks
 

phillychris498

Well-Known Member
I've had my bars raised very high the last few rides being conservative with issues I've had with my neck. Next ride I'm gonna try bringing them down a few spacers and seeing if it helps with ups.
 

jackx

Well-Known Member
I've had my bars raised very high the last few rides being conservative with issues I've had with my neck. Next ride I'm gonna try bringing them down a few spacers and seeing if it helps with ups.
Sounds like a good idea to try. Less spacers should help to shift your weight forward slightly.
 

RSAmerica

Well-Known Member
Sounds like you need a longer stem & slide your seat forward to get more weight over the front. This will give you more front end grip and make it easier to get over slow speed tech plus it will make the front feel less floppy. Try at 50mm stem.
 
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