Matching Stem Length with Fork Offset 8

Brian Cahal finds out how matching stem length with fork offsets affects steering performance using a Fraezen 44mm stem and PNW Range 35mm bar. 

Credit: Brian Cahal
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Stems
Handlebars
Brian Cahal
8 comments

View replies to: Matching Stem Length with Fork Offset

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bizutch
1 year ago

I took the parts off my old frame and put them on the new frame.  

I've been riding it ever since.  Not gonna even think about stuff.  

Just gonna ride.

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pernyberg
1 year ago

Great video but missleading title. Its a good thing he clearly states that the bars had more of a difference in irde characteristics than the stem. 👍

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Fred_Pop
1 year ago

I'd be more interested in bigger differences in stem length and backsweep. I've tried -10mm, 10mm and 20mm with the same 9º backsweep and also tried 17º backsweep with 20mm stem. I like the extra backsweep for long days out in the saddle as it's comfortable but I felt like I didn't have enough weight on the front end. Perhaps the 17º backsweep with a longer 30-40mm stem would work better. Gone back to my regular 9º bar witgh 20mm stem now.

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marc2211
1 year ago

Comparing stem lengths that are 1mm different while also changing the bars to ones with different backsweep etc. Really, nonsense. 

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AgrAde
1 year ago

Wow, that's absolute nonsense. Throw it on the large pile of snake oil and bad science that we have in this sport.

The only thing that matters is where the grips are relative to the steering axis (grip offset). Where the bars and the stem clamp together is irrelevant. So many people swear by a particular stem length even when comparing vastly different bars, and the bars usually make a larger difference than the stem. Especially riser bars which change the grip offset a truckload depending on what angle they're rolled to. Even bars with the same sweep angle can give you a different grip offset because the bend in the bar is closer or further from the middle compared to another set.

Fork offset isn't even a direct factor in the steering behavior and there's no reason it should be a consideration when setting up your bar and stem. It's just used to tune the trail, which is essentially the offset between the tire contact patch and the steering axis.

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just6979
1 year ago

Hundo percent nailed it. Stem to offset comparison is nothing. Fork offset to grip offset _might_ be something, but probably not. Even if yes, the relationship would change with head angle as well. 

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dirty booger
1 year ago

For sure.

I measured the setback on three different bars (Speshy alloy, OneUp, and WAO) all with 8 degree back sweep, and all cut to the same length. The actual offset at the grips was 50, 40 and 32mm! It makes a huge difference where that 8 degree back sweep actually starts.

Agree or not with his RAD measurement ideas, Lee McCormack has some great info and calculators to determine and compare SHO (steering/hand offset). https://www.leelikesbikes.com/

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benthandlebars
1 year ago

Super misleading title. He switched from a 9 deg backsweep to a 10 degree. That would move the ends of his bars about 6mm backwards alone. The stems were only 1mm different. Depending on his bar roll, his hands were roughly 7mm back with the second setup.

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