Posts
2400
Joined
11/9/2011
Location
Denver Metro, CO, USA
Edited Date/Time
11/25/2020 4:25pm
Guys,
Years ago when riding a lot of desert in Arizona, I fell in love with the 90mm wide front tires that were relatively new on the scene (circa ~ 2010?).
Now as I'm transitioning back to MX and singletrack in Colorado, I've been riding both width tires: 80 and 90mm widths.
I'd like to hear your general thoughts on the pros and cons of each width.
As always, thanks the outstanding feedback that will come my way in advance!
Years ago when riding a lot of desert in Arizona, I fell in love with the 90mm wide front tires that were relatively new on the scene (circa ~ 2010?).
Now as I'm transitioning back to MX and singletrack in Colorado, I've been riding both width tires: 80 and 90mm widths.
I'd like to hear your general thoughts on the pros and cons of each width.
As always, thanks the outstanding feedback that will come my way in advance!
So, in the cases of the following tire sizes, here are their corresponding heights (not diameters!):
(1) 80/100-21 --- 80mm x 100% = 80mm
(2) 90/100-21 --- 90mm x 100% = 90mm
Therefore, a 90/100-21 tire is 10mm (~ 0.4 inches ... almost a 1/2 inch!) taller than an 80/100-21. This is NOT trivial as AxlBundy points out (BTW, I'm from Blaine, MN - grew up on Laddie Lake).
Yeah so it raises the front end 1/4". 90/90s are the same height.
It raises the front 10mm, almost 1/2 inch. The 10mm difference between an 80 and a 90 is in the sidewall height, not the overall height of the tire. The overall height difference would be 20mm.
A 90/90 would have an 81mm sidewall. So, in theory, 1mm taller than an 80/100.
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To make it more confusing not all 80/100 are the same width or height even within the same brand. Mx3s/33 are wider than mx34 for instance.
90/100-21 for high speed square edges/rocks/roots.
80/100-21 everywhere else.
Do any 20” fronts still exist out there in the world?
I just went in PU and sorted all tires by 20" and all that came up was ATV/UTV stuff.
It has been years since I ran a 90 front.
I don't feel like the 90 gave any improved grip on hard pack / blue groove or stuff like that when I tried them, but it doesn't settle into a rut as well for me.
I rod hard pack clay yesterday on a Bridgestone X30 front (YZ250) and Maxxis MX-ST front (MC350F).
Both bikes have 80 front tires and KYB spring forks. I felt like the front end grip was superb and I could basically do no wrong.
The one track I can think of where the 90 might be an equal or slight advantage is the type of sand that packs down with a hard base. We have a track called Toutle MX (formerly known as Riverdale MX) here in Washington. The conditions there might warrent the extra contact patch you can get from a 90. Another track out east called Horn Rapids MC (Richland, WA) has a very rough loose over hard sand condition pretty often and that may also work well with a 90. Lots of guys run the scoop tire in the rear at HRMC, despite the harder base.
FWIW - after posting this in 2020, I have a fair amount of 80-width ride time and it's head and shoulders better than 90-width for single track in the mountains and motocross for me.
The 90-width definitely has it's place, but for me it was open desert where I wasn't constantly laying the bike over for the next turn. For turns/precision front-end work, I just never gelled with the 90.
I used to run a 90 on my '05 YZ125 and loved it in that application. It just gave me a slightly stickier feel on the front and helped with the generally "unturnable" nature of the bike. Oddly enough, I didn't like it as much when I moved to the YZ250.
I have tried running a few different 90 width tires on the front of my FE 350, and have had similar experiences. The 90 width has it is advantages in absorbing chunk & square edged, rocky hits, but the front end just hasn't felt as precise with the larger tires. Pretty sure I will be going back to an 80 series tire once this front wears out.
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