Road Bike, Cycling Forums banner
1 - 20 of 26 Posts

· Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi All,

I'm seriously thinking of a Salsa LaCruz frame but I've never ridden a cyclocross bike and I'm wondering if there is anything I need to know, particularly with regard to frame size.

Currently I commute on a 29er but the LaCruz would be a better solution to my particular route to work. I can take across most of the components including a Rohloff hub so it's just the frame I need. I plan on using a flat bar as well - is that frowned on by you guys? I sort of have to to use the Rohloff shifter and my disk brakes.

I'm between 5'10 and 5'11 with a 32" inside leg.
My 29er is a Niner SIR9, Medium which has an effective top tube length of 23.75".
The LaCruz with the equivalent effective TT length is the 59 which would be far too big.
I suspect I need the 55 but the top tube will be shorter - Is that taken care of by the drop bars stretching the rider?

Try one on I hear you shout. I'd love to but there isn't a dealer that I can get to with any stock and will probably have to buy the frame on the internet.

Any advise greatly appreciated.
 

· Registered
Joined
·
116 Posts
MTB bikes and road bikes are 2 different monsters, geometry-wise. I believe mtb bikes have longer top tubes to allow the entire front end to be more stretched out. This allows less chance of toe overlap and a longer wheelbase for better stability. These are just my guesses, since I have no first hand bike building experience.

Road bikes (and CX bikes for that matter) have a shorter top tube. I'm the same height as you and I would get a 53 cm La Cruz. In that size, the "traditional sizing" is 56cm which is what I have always been on a road bike. I have Fisher Ferrous size 19" and that top tube is something like 63cm, which is nuts. I know this because I tried putting road bars on it and found I'd have to put a 60cm stem on it to get close to feeling "road-ish." It feels fine with flat handlebars, which is the way it should be.

Now, if you want a more mtb feel since you're going with a flat bar, you could maybe go with the 55cm. I'm not sure how much that will affect handling since it might put the wheelbase way too wide for you. If you can, go to a local bike shop and try out a 56cm (53 La Cruz size) and 58cm (55 LC size) bike to see which one fits you best. I think you'll find a road, or a different cross bike, with a 56-57cm top tube to be just about right

Hope this helps. I would love to get a La Cruz, but I'm trying to pay off bills this year, not get a new bike. Oh, and go with whatever setup you want on that bike. The traditionalists may say it's not a real CX bike, but if you can use all your parts and are comfy, that's all that matters. And anyway, the discs take it out of the traditional cross bike type-set anyway, so have fun with it! Put some mustache bars or Mary bars on it for a goof! That'll really get to the bike snobs.
 

· Registered
Joined
·
5,270 Posts
carnifex said:
Salsa has a strange way to measure their frame size, so taking this for estimating the proper size is questionable. I would rely on the eff. TT only.
I disagree on both counts. First, Salsa is nice enough to include a "traditional size" column in their geometry charts, which accounts for the sloping top tube and is ideal for sizing the frame. Second, top tube is only half the story when it comes to computing the reach from saddle to bars, seat tube (length and angle) being the other.

I don't think comparing numbers from a 29er frame to a road frame is the best way to go about it, even if you plan on using flat bars.

I recommend using the Lemond formula (.67 x public bone height = traditional size) to choose the frame.
 

· Registered
Joined
·
21 Posts
Funny thing is, I just measured my LaCruz 51 frame, it is shown as 54 traditional (this is measured just below the seat post clamp, never saw a frame manufacturer measuring that way), in fact the seat tube is 55,5cm from center BB to top, so what is it to disagree about?

The seat post length doesn´t help me at all in calculating the proper fit, the angle is to take into consideration, ok.
 

· Registered
Joined
·
5,270 Posts
carnifex said:
Funny thing is, I just measured my LaCruz 51 frame, it is shown as 54 traditional (this is measured just below the seat post clamp, never saw a frame manufacturer measuring that way), in fact the seat tube is 55,5cm from center BB to top, so what is it to disagree about?

The seat post length doesn´t help me at all in calculating the proper fit, the angle is to take into consideration, ok.
According to the La Cruz geometry chart, your seat post is supposed to measure 51mm from the center of the BB to the top of the top tube.

Traditional frame size is the seat tube C-T assuming a horizontal top tube. It absolutely helps determine the proper fit, because it relates the height of the saddle to the height of the handlebars.
 

· Registered
Joined
·
21 Posts
But you were talking about the traditional column too, weren´t you? So I just wanted to point out that depending on actual ways of measuring you can end up totally wrong with just dependung on ST. As you wrote 51 is C-top of TT, I didn´t say anything against it, did I? It is not only supposed to be like this, it actually is, so what? But the traditional dimension shown isn´t any good in estimating proper sizing as you tried to implicate.
The combination of angles and TT is another matter. So don´t just cling to your ST.
 

· Registered
Joined
·
5,270 Posts
carnifex said:
But you were talking about the traditional column too, weren´t you? So I just wanted to point out that depending on actual ways of measuring you can end up totally wrong with just dependung on ST. As you wrote 51 is C-top of TT, I didn´t say anything against it, did I? It is not only supposed to be like this, it actually is, so what? But the traditional dimension shown isn´t any good in estimating proper sizing as you tried to implicate.
The combination of angles and TT is another matter. So don´t just cling to your ST.
Seat tube length has been used for countless years to determine the proper frame size and has proven itself a very reliable metric. The only reason we have to talk about "traditional" size is because most bikes are now built with a sloping top tube.

On the other hand, your method of matching effective top tube puts a guy who is between 5'10" and 5'11" (about 179cm) on the very largest frame Salsa offers, which is highly dubious.
 

· Registered
Joined
·
3 Posts
Discussion Starter · #12 ·
Thanks for the info and the discussion. I think the only safe way is to get the size right is to try one and that is not going to happen soon but it could happen so I'll keep going with the niner for now. I'm in Australia and just comming into winter. The Niner doesn't have mountings for fenders. A clip on keeps the worst off the rear but I get a face full of water from the front. Still it doesn't rain much (or enough) so I'll be content. :)

Cheers
 

· Registered
Joined
·
5,270 Posts
cowdotpat said:
Thanks for the info and the discussion. I think the only safe way is to get the size right is to try one and that is not going to happen soon but it could happen so I'll keep going with the niner for now. I'm in Australia and just comming into winter. The Niner doesn't have mountings for fenders. A clip on keeps the worst off the rear but I get a face full of water from the front. Still it doesn't rain much (or enough) so I'll be content. :)

Cheers
Use the Zinn cycles frame-size calculator. Take the measurements very carefully. Post your measurements and the results from the calculator.
http://zinncycles.com/FitIntro.aspx
http://zinncycles.com/fitsystems/DimensionPage.aspx

When I was shopping for a bike, the bike shop measured me using all kinds of fancy widgets, and the recommendations that popped out were very close to what I got myself from the Zinn calculator. Certainly close enough to choose a frame size.
 

· Registered
Joined
·
39 Posts
I'm the same size

You would be on the 53 based on your measurements, you should be on a traditional 56 frame, but torso and arm length could male you a 55-57. If the standover allows move up to the 55, Salsa lists 32.8 center of top tube but it should be close. Standover for this will be as important as the seat tube length and eff top tube. You'll need a longer stem to run the flat bars either way to make up for the foreward curve of the drop bars. Go to a local shop and stand over a 57-58 size and see what your comfortable standing over.
 

· Registered
Joined
·
64 Posts
It may also be that the La Cruz won't fit you all that well. I was considering one, but passed because of its geometry. The effective top tubes are reallly long compared to the seat tubes.

I am 5'11" with long legs (34" cycling inseam) and a short torso. I like a frame on which the seat tube is roughly equal to the top tube. My 57cm Litespeed with a 565cm top tube and a 100cm stem fits me perfectly. In order to get close on a La Cruz, I would be on a 53cm Salsa with a mile of seatpost (I like a 775cm seat height). The eff. top tube on the 53 is 570, so I'd need a shorter stem and I'm sure the bars would be way down there.

I think it would swing a leg over one before I bought it.
 

· Registered
Joined
·
5,270 Posts
If the Litespeed is a traditional frame, then the 53cm La Cruz is shorter by 1cm in the vertical and longer by 5mm in the horizontal. In other words, put one extra spacer on the steerer tube. You would have 4cm more seatpost showing, but that's irrelevant.
 

· Registered
Joined
·
21 Posts
Hello, just to comment on possible "miles of seatposts".

I ordered a 51cm La Cruz, I am 1.85m (yes, we are metric over here in Europe)
My seat height is around 77cm, so with the 51er actualy sporting a 55.5cm seattube, what is exactly the lenght of the effectife TT, I have a free seat post length of 17cm with a 45mm saddle. This is in the range of modern sloped road frames and much less than in MTB. I will run the La Cruz with a 120mm stem. With up pointing stem I get only about 3.5cm of the saddle above the bars, with 25mm of spacers installed. The next frame would be 25mm more HT length, this is something to consider too.
 
1 - 20 of 26 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top