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Old 11-29-2018, 07:17 PM
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Wayne77 Wayne77 is offline
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Another frame geo thread...working around a bike with short trail

Some of you might have seen the PSA about the crazy good deal going on right now for the XSogn (by Rawland). So I'm looking at that bike hoping I can make it work for my wife who I'm hoping to get into gravel riding. She doesn't like roadbikes & narrow tires and the "pressure" she feels to go fast (that's not coming from me...I think she's putting that pressure on herself). Also, she hates riding in traffic so I'm hoping a more relaxed / outdoorsy / cushy tire kind of vibe would be just what she needs. Anyway, I digress...

One strike against the XSogn is that it only comes in 3 sizes. Therefore I'm looking at both the "56" and the "59" for my wife. I'm pretty well versed in the stack and reach she needs for a proper fit, and therefore I know what concessions need to be made between each of these sizes when ideally I think my wife needs something in between.

With her current road bike her bars need to come up about 2cm. She's fits the classic short torso/long legs female profile so I don't think her bars need to come forward too much, but a cm further out is probably ok. Let me stress however that this thread isn't primarily about fit, I just need to figure out what handling impacts we'll deal with between the two very different sizes, especially since the stem is where we'd have to make some adjustments. On paper the handling impacts of a longer wheelbase are pretty obvious but its not that simple. Here's the catch - both bikes have a shorter than average trail (32mm). With the short trail a constant, and stem length being the variable, I'm wondering how the handling on a short trail bike will change with varying reach and stem lengths. Not only am I trying to understand how a short trail affects handling of this bike across the sizes, I'm also wondering whether stem length and or front center will either increase or decrease the impacts of that short trail.

**Note that currently she is riding a frame with reach of 37.6cm and stack of 56cm, and as mentioned she has 3cm of spacers, a positive rise stem, and her bars tilted up more than normal to get the hoods to where she wants. She's 5'9", seat height is 71.5cm. Current frame is a 55cm. I think ideally she should be on a 56cm road bike. Also I want to get her bars back to a reasonable tilt so she can reach the brake levers easier when in the drops. Current saddle tip to bar length is 50.5cm, saddle setback 6.5cm**

**I used an online frame calculator to derive the resulting measurements below**

Option 1: 56cm XSogn - same stack (56xm), slightly longer reach (39.3cm), ~2.5cm shorter trail) The Xsogn also has a 73.5 (vs 73) STA so that possibly makes it feel a little longer than a typical 56cm frame. If we go with this option, I think the extra reach is ok but we'd need one or 2cm more spacers under the stem to get the hoods where they need to be. And I'd probably need another to accommodate for the lower hood height occurring when we rotate her bars back down. Basically it seems like this frame is about the right length but the stack is still 2-3cm lower than I'd like.

Option 2: 59cm XSogn - Accommodate for a longer reach than normal for a bike her size by using a 2cm shorter stem / stack is 3cm higher (59cm vs 56cm) than her road bike...again a short trail of 32mm).. Certainly a 59 would normally be out of the question for someone needing a 56. That said my wife currently has a 9cm stem, so using a 70mm brings the bars back so the saddle to bar distance is a reasonable 52cm (currently she has 50.5cm and I think she could probably use an additional 1cm of reach as is)

My gut tells me that option B...even with a shorter stem to create a comparable cockpit length, will feel way to long due not only to the longer front center but also due to the short trail. Is this correct? In a nutshell how would a 58-59cm bike with a 70mm stem and short 32mm trail handle? Would wheel flop be an issue with the short trail? I imagine the short stem and lighter weight rider will pull weight off the front wheel...and that's last thing you would want to on a bike with really short trail correct? Or is it better to move your weight back on a long bike with a short trail?

Sorry for the really long post... As the dust settles, it seems like its a choice between two less than ideal situations: smaller bike that is long enough but too short, or a long bike with a short stem that may handle really poorly.

(All this obviously means it may not be a wise purchase...I know that's the default answer here, but lets set that aside just to keep the discussion focused on trail, handling, how it relates to longer vs short frames, etc):

If any of you are still awake I'd love to hear your thoughts!

Last edited by Wayne77; 11-29-2018 at 07:30 PM.
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Old 11-29-2018, 09:30 PM
l0n3rider l0n3rider is offline
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1st of all .. i do not have anything to value add .. but if you would like to erad further into bike handling .. this is an excellent article on cyclingtips.com

https://cyclingtips.com/2018/11/the-...-the-steering/
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Old 11-29-2018, 11:59 PM
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Quote:
Originally Posted by l0n3rider View Post
1st of all .. i do not have anything to value add .. but if you would like to erad further into bike handling .. this is an excellent article on cyclingtips.com

https://cyclingtips.com/2018/11/the-...-the-steering/
I just got done reading through the entire article. What a great resource! Thanks for sharing this. In the case of the longer frame 59cm XSogn, it’s no simple equation obviously but some of the main the factors from my case above are starting to gel for me like this:


- Long wheelbase / long chainstays: more stable at speed a little harder to maneuver at slower speeds.
- Short Stem: small steering arc / easier to turn the wheels / quicker steering
-Less Weight on the front wheel due to a lighter rider using a short stem to compensate for a long reach: lighter steering action oversensitive to steering input
Short Trail: more manueverable at lower speeds / less stable at high speeds.
Novice Rider: more prone to overcorrect / overreact when correcting a line.

= ?

Maybe I’m reading this wrong but, with the longer frame in my example, it seems that there is one factor on the “stability at speed / slower at low speed side” part of the equation, and 3 factors on the “fast steering at slow speeds / twitchy at high speeds” part of the equation. So the key question is whether all those factors override the longer frame...resulting in a less than stable / twitchy situation, made worse by a novice rider prone to overcorrection.

Im thinking this bike isn’t going to be ideal in either size because the 59 just isn’t going to give me wife a relaxing experience with some unstable characteristics while the 56 may be a little better in the handling department but to make it fit we’d have to resort to some less than attractive measures to get the bars high enough. Clearly I need to be looking at other frame options or I risk this whole operation to sell my wife on cycling ending in heartbrake and misery for all involved and my wife swearing off cycling for good :-)

As I mentioned in the other thread. The geometry approach here by Rawland here is a head-scratcher. Not only is it only offered in 3 vastly different sizes, but the geometry in each size seems quite long and low for a gravel or adventure bike...add in the real short trail and I just don’t get it. Maybe I’m still off base here and would love someone to set me straight. Either way it’s been an interesting case study. I’m really glad I took the time to research this before pulling the trigger. It’s a bummer because it’s a nice looking steel frame, love the paint color, Apex 1x drivetrain, hydro brakes, stock WTB tires and for some reason Walmart got their hands on a huge batch of them and they’re selling them for $950! If the dimensions work for anyone looking for a low cost gravel bike (with a spec closer to $2K) it’s a no-brainer!

Last edited by Wayne77; 11-30-2018 at 12:02 AM.
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Old 12-01-2018, 06:54 AM
ultraman6970 ultraman6970 is offline
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If the wheelbase is longer, you will need a longer stem to keep the same handling you are used to, in other words IMO maybe go to a smaller size frame, with some manufacturers is not an option because you end up with a frame way too small... which means compensation in length by using more drop in the handlebars, which is not ideal for some folks specially if you are getting old, in which case you are starting to get smaller not bigger in height and reach. I have like that problem with some colnago models, their wheelbase in my size is like the wheelbase of a like 59/60 frame, handling is a must for me so it bothers me.

The key word here IMO is "it will bother you?", some folks dont care about the handling at all, in my case 1st thing is always handling and have a bike that goes where i want to quick, then comfort is a thing i can work out.

THe look kg series with adjustable drop outs, you can feel the difference that makes big time....
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Old 12-01-2018, 11:50 AM
OtayBW OtayBW is offline
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Quote:
Originally Posted by Wayne77 View Post
With her current road bike her bars need to come up about 2cm. She's fits the classic short torso/long legs female profile so I don't think her bars need to come forward too much, but a cm further out is probably ok. Let me stress however that this thread isn't primarily about fit, I just need to figure out what handling impacts we'll deal with between the two very different sizes, especially since the stem is where we'd have to make some adjustments. On paper the handling impacts of a longer wheelbase are pretty obvious but its not that simple. Here's the catch - both bikes have a shorter than average trail (32mm). With the short trail a constant, and stem length being the variable, I'm wondering how the handling on a short trail bike will change with varying reach and stem lengths. Not only am I trying to understand how a short trail affects handling of this bike across the sizes, I'm also wondering whether stem length and or front center will either increase or decrease the impacts of that short trail.

**Note that currently she is riding a frame with reach of 37.6cm and stack of 56cm, and as mentioned she has 3cm of spacers, a positive rise stem, and her bars tilted up more than normal to get the hoods to where she wants. She's 5'9", seat height is 71.5cm. Current frame is a 55cm. I think ideally she should be on a 56cm road bike. Also I want to get her bars back to a reasonable tilt so she can reach the brake levers easier when in the drops. Current saddle tip to bar length is 50.5cm, saddle setback 6.5cm**
A few general comments:

- At 6ft tall, I wouldn't ride a 59cm frame myself. Without additional info, I'm surprised that this would even be in the ballpark for your wife.
- I think more in terms of contact points (distance to bar center, or hooks, or hoods, or whatever works for you; saddle height; setback; drop, etc.) than I do frame stack and reach which really don't mean much to me personally.
- With trail ~20+ mm less than a 'coventional trail' for a road bike in those size ranges, I would think that while low-speed handling would be stable, decreasing stability at higher speeds might be less comfortable for her if she's not used to that kind of handling.

I dunno. I would find a way to let her make the determination herself, if you could, based on her own comfort level in fit and handling. GL.
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Old 12-06-2018, 08:26 AM
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weisan weisan is online now
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Wayne pal, I don't know what the right answer is to your wife's fit issue but I do applaud your continuous effort to make things better for her and encourage her along the way.

For some reason, I thought maybe you can take some inspiration from Ms Cools....in my mind, the Velo Orange Polyvalent would be a better choice than the Xsogn because a) it will ride less like a tank b) more maneuverable c) prettier...

https://velo-orange.com/products/polyvalent


Maybe you can watch these videos of Ms Cools with your wife:
https://www.youtube.com/watch?v=cn4p9OHgBCA&t=345s

https://www.youtube.com/watch?v=YdvLCbwg2yo&t=11s
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Last edited by weisan; 12-06-2018 at 08:51 AM.
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Old 12-06-2018, 09:07 AM
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Wayne77 Wayne77 is offline
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OMG, that is beautiful! Love that frame...for the price that is hard to beat. I’m absolutely going to check these videos out with my wife. It’ll be hard not to snag one for me as well.

Thanks Weisan pal!

Also, thanks a ton to OtayBW and Ultraman for your thoughts - very helpful.
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