jambon

Hi all ,

Have nearly finished saving up for a 700cc disc trucker so I’m now starting to think about a frame size . I was hoping a few people here might read through my reasoning to see if I have missed something .Based on my measuremens I reckon that I’m a candidate for either a 60 or 62 . I had a look at the Surly owners Size spreadsheet but I found the range of sizes that people my height were riding kind of confusing , from 58 s right up to 64 s ! Please bear in mind that I am going for bars at least level with the saddle for an upright comfortable touring position .

My measurements ;
Height – 6 foot 2
PBh – 94 cm
Saddle height (PBH – 10 ) 84 cm approx

My height comes from mostly leg and a long neck and head . I have the torso of a much shorter person . My arms are not particularly short .

From the Surly site the 62 cm has a standover height of 866.5mm so with my PBH of 940mm I think I should be fine for standover on both bikes .

When it comes to saddle height (84cm ) I’m thinking the 62 wins as with the 60 I may not be able to get the bars up that high . I also have to figure in that the higher I bring the stem up the steerer tube the shorter the reach will become due to the angle of the headtube . This could be a good thing if I go 62cm and a bad thing If I go 60 . I will specify to the shop that the steerer tube be left uncut to allow me to tweak .


As well as the above reasoning I also used a frame fit formula that I found in an older thread .

It’s ; Basic bike size=.67 of PBH so for me that ‘s .67 x 94 = 62.98 ( round up to a 63cm frame )

Then ;

“Top tube length modifier is a ratio of overall height divided by true inseam height. If it is greater than 2.2 then a longer top tube (maybe larger bike) is indicated. If it is less than 2.0 then a shorter top tube (smaller bike?) is indicated. This measurement corrects for long or short legs/short or long torso.”
So in my case ; 187.96/94 =1.9

So that puts me on a 62cm frame I guess . Any thoughts ?

fietsbob

Go to the other posting

Mr IGH

I just went through this exact sizing process. The LHT and Disc Trucker are kinda goofy, esp the 60 and 62. While the top tube lengths (ett) are different, longer on the 62, Surly relaxed the 62 seat tube angle compared to the 60. As a result, they have the same reach, both size frames will use the same size stem. I would go with the 62 for the longer head tube, but even this doesn't really matter, both frames have the same fork, the difference will be 20mm of spacers, fit is the same.

I'm 6-2, I wanted to use a Thudbuster, I bought a Soma Disc Saga instead (the size they call 60, which has a similar reach and 57.5cm seat tube). If the Disc Trucker had a sloping top tube I would have bought it.

tarwheel 

Are you wedded to the idea of getting a Surly LHT? They are fine bikes, but the geometry is all wrong for me. Fit is the most important issue when buying a bike, so it makes sense to consider alternatives if the fit on a particular frame is not ideal.

If you are open to other options, I would encourage you to check out the Soma Saga, which is available in disc or canti brake versions. The Saga has a taller head tube and shorter top tube in sizes comparable to the LHT. I bought a Saga a few months ago, and the fit is perfect for me. It replaced a frame that had a head tube a little too short and a top tube a little too long, and it's made a big difference in my fit and comfort. The Saga costs about the same as a LHT and is equivalent in every respect with regard to touring capability. The only advantage a LHT might have is room for larger tires, but the Saga will handle tires as large as 40 mm and maybe more, which is plenty enough in my book.

jambon

Thanks tarwheel , that Saga looks great ,unfortunately Soma doesn't have a dealer in my country . I am kind of wedded to the idea of a disc trucker , people that have one just seem to love them ,

jambon

Thats Mr IGN , good to know that . The LHT does indeed seems like a tricky bike fitwise . Going with the longer headtube makes sense especially when my saddle height will be pretty high . Hopefully there will be minimal playing around with stems to get the reach right .

Mr IGH

The reach is slightly shorter on the taller frame, by a couple of mm, that means you'll use the same stem length for either frame.

The only real difference is the head tube length (stack), the fork is the same for both sizes. That means the steerer tube length is the same size, 350mm. The only difference is that you'll need an extra 20mm of spacer on the 60cm vs the 62cm to have the same stem stack height.