illjustride

Hi folks, I've been looking at the geometry on a new build I'm putting together and before I get the frameset I wanted some insight. I'm 6.1' with a 34inch inseam. I'm building a gravel bike with the Ibis Hakka MX. My current road bike is a Trek Emonda ALR 58cm with an H2 fit that has a headtube angle of 19cm (190mm) whereas the 58cm Ibis Hakka MX has a 175mm and 61cm 195mm. The Ibis Hakka MX 58cm has a far lesser headtube length than my Trek Emonda which would put the frontend a bit lower I suppose. However, the 61cm Hakka MX has a 195mm headtube which is taller than my Trek's 58cm. As for the seat tube angle on my Trek Emonda it's a5 73.0 degrees and both 58cm and 61cm Hakkas are at 73.5 degrees. I'm not sure if this will be a big impact on me. As for effective top tube, my Trek Emonda ALR 58cm has a 57.3cm (573mm) effective top tube and the Hakka MX 58cm has a 570mm and 61cm has 590cm.


As for my current 58cm Emonda I feel that it's a comfortable ride but my Seatpost sticks up pretty high and I'm running 172.5 cranks. Some people at the bike shop tell me I should have sized up on the frame and went with a 60cm so it's too late for that. But with my new gravel build, I was thinking of going with the Hakka MX in a 61cm. I'm not sure though. Can someone shed some light on sizing on these two frames and tell me with my measurements and geometry listed if a 61cm Hakka MX would be the better one to go with. All help appreciated.

berner

I just saw your post an hour after re-reading about bike fit by Lennard Zinn, a custom bike builder. He has a fine book entitled "Zinn And The Art of Road Bike Maintenence". The book has a good section on bike fitting. His website, https://zinncycles.com/, also has a section on bike fitting. I've not gone through the calculation on the web site but the bike book fitting advise is spot on for me.. Good luck.

Fredo_Adagio

Please excuse me if this seems too much of a rant.

There is a complete disconnect between the way bikes are configured in advertisements and the way they are configured to fit real people.

The last road bike I purchased was a Kestrel Talon X. The size chart on the website showed that at 5' 7" I am at the small end of Medium (55 cm) and the tall end of Small (52 cm). Based on past experience, I went with Small. I have found that in order to get a decent drop from the seat to the handlebars, I need to opt for the smallest frame I reasonably fit.

Here is how the bike is shown on the Kestrel website.



Here is the bike as I actually rode it.



Note that the website photo has about three more inches of seatpost exposed and all the spacers below the stem. I have both the seat and the handlebars lower, and I had chosen the smaller of the two frame sizes recommended by the website for a person of my height.

I'm picking on Kestrel here, but the situation is the same for other bike brands. Actually, the situation is worse for triathlon bikes as the advertisers play games to make the bikes look less gawky by showing the seat unreasonably far aft and showing the bike equipped with deep section wheels that are an extra-cost option.

If you watch the Global Cycling Network on YouTube, you can find videos of Simon Richardson (6' 0") talking about his own bikes and how he goes down a size relative to the manufacturer's recommendation. You can also find videos of Emma Pooley (5' 2") talking about how her bike fit is compromised by the frames available at the small end of the size range. Ideally, she would ride a bike with 650 size wheels, but the neutral race support mechanics carry only 700 size wheels.

illjustride

Thanks. I did some measurements with my girlfriend based off your link along with another I found and looks like I should be on a 60cm-61cm frame. Wow

DaveSSS 

Start with an accurate saddle height. Mine is 73cm. Unlike the picture posted above, my seatpost exposure is long and my saddle to bar drop is also large at 10cm. To get that much drop, the stack height on my frame is 527mm, with a 15mm headset top, no spacers and a -17 stem. A -6 stem would raise the bars about 2cm.

You can extrapolate a stack value, with reasonable accuracy just from this info. If your saddle height is 2cm higher, add 2cm to the stack. If you want less saddle to bar drop, add more stack or up to 2cm of spacer. If you need more than 2cm of spacer, consider the next bigger size, or look into an endurance frame with a taller stack.