Mountain Bike Reviews Forum banner

Relative Anti Squat Profiles Published! (finally)

12K views 92 replies 34 participants last post by  smilinsteve 
#1 ·
Thanks to a local engineer to helped my find the linkage program - here are a few anti squat profiles showing how ventana's stack up compared to a DW link and GT Idrive. These are just a few examples for refernce purposes only.
 

Attachments

See less See more
3
#78 ·
ronny said:
Read em all and you seem to be the loudest voice on each thread. I know what you are getting at and you actually come across quite logically in most of the threads. Ventana bikes are single pivot and the pivot placement is pretty much the same on all the bikes except the dh model. I know that Ventana is going to bob a little more than most brands with a higher pivot placement or different suspension design. With that said, the vast majority of Ventana riders are happy with their rides. As said previously, the whole is the sum of the parts. Always a compromise.

One thing I am wondering is there is rarely any complaints about the Terremoto with excessive bob or squat. The pivot placement seems pretty low. I wonder if there is less complaints because Terremoto riders are using coil shocks or what? Does the extra travel mask the problem or would the bike not wallow in it's travel even more? Moto users please chime in. IheartVentana, what are your thoughts?
There's any number of reasons why terromoto riders haven't voiced concerns as much - including coincidence.

Being that all ventana suspension bikes other than the cuervo have identical wheels paths, there's no reason to think the terremoto has any different characteristics than the salty, ciclon or bruja.

Yep, I've been pretty vocal on this forum. My goal is to fight ignorance. It's harder than I thought!
 
#79 ·
iheartbicycles said:
A few points of clarification.

The numbers posted are all derived from a gear ratio of 32/30 - which I picked just cause it's a common climbing gear - but antisquat curves change based on gearing - so each bike will differ a bit based on this.

Generally speaking, the lower the gear in the front - the more anti squat and the smaller (higher) the gear in the back, also the more antisquat. The converse holds true as well.

Also - the anti squat posted for each bike is at top out - assuming sag of 20mm or so, each bike will behave a little differently. I haven't checked each - but of the ones I have (dw and ventana) antisquat decreases during suspension compression.
I've been avoiding this thread cause it looked like math was involved. . .

But, it's pretty interesting, actually. I appreciate these points above. My impression was that the old Turners and the Ventana XC/trailbikes had pivots as low and close to the BB as they do to improve pedaling efficiency in the 22t ring up front while maintaining stiffness through to the rear-wheel. This certainly mirrors my trail experience as I ran 1x9 last year and 2x9 starting a month ago. The difference is noticeable to me climbing even with the same gear ratios. It'd be cool to know what the numbers were with 22t up front.

Likewise, I wonder how the anti-squat changes through the sag. Intuitively, you're right, it should decrease, but I doubt it's a linear relationship for bikes with VP or DW links, as chain growth isn't linear on these bikes. I dunno, just sayin.

Also, there are a lot of 0's plugged into the program (that I can see on the 1st pic anyway). Front and rear susp sag, etc. Wonder what these values do to the anti-squat number when changed to match real riding conditions?

Lastly, is there an upside to the design that made Sherwood pick it? Is what I heard about the lateral stiffness and small ring pedal efficiency just bunk? Certainly the Propedal "fixes" the problem for my riding style, just wondering if there's an upside.

Anyhow, I guess I did feel a bunch of squat on my Ciclon pedaling around in 32 or 34 up front and going up steep hills. Now that I broke down and got a granny, it seems to have lessened considerably. Now feels better than my last bike (FSR design), but much, much stiffer laterally.
 
#87 ·
#85 ·
Thanks man!
So, I assume that (32/15), is the gear combo for that anti-squat curve, which he seems to use as a standard for comparison. Wouldn't it be better to use a small ring gear combo (22/28 for example) since you would be most interested in anti squat during steep climbing?

Now that I think about it, how much meaning does a graph like that even have?

If you are comparing 2 different bikes, all you are really looking at is the amount of anti-squat in that gear combo, which might not be representative of any other gear combo, or is it?
 
#91 ·
Thanks man!
So, I assume that (32/15), is the gear combo for that anti-squat curve, which he seems to use as a standard for comparison. Wouldn't it be better to use a small ring gear combo (22/28 for example) since you would be most interested in anti squat during steep climbing?

Now that I think about it, how much meaning does a graph like that even have?

If you are comparing 2 different bikes, all you are really looking at is the amount of anti-squat in that gear combo, which might not be representative of any other gear combo, or is it?
the Linkage program defaults to really weird gear combos. You have to choose the gearing you're looking for. And i agree - we're interested in climbing gears, not downhill gears.
 
#88 ·
You're right, but the site has lots more info on lots of bikes, including Alpino, Zeus, and El Cap. Here's another image for the "new" Ciclón:

View attachment 829479
It is interesting that the A-S curves are completely different in the 3 chain rings in this example. In the large ring, A-S increases dramatically as you move to larger cogs. In the middle ring, A-S increases more gradually moving into larger cogs. In the small ring, A-S decreases as you increase the cog size.

I can't really picture an explanation for those numbers, but it goes back to my point that an A-S number , or an A-S curve on a specific gear combo isn't that informative of a bikes performance.
 
#92 ·
While I don't expect to understand the numbers, I can tell you that there is a HUGE difference in the pedal bob from going to a 1x from a 30T to a 28T. The 28T was so horrible that it lasted one ride before I switched back to a 30T (2012 Ciclon). My rear cassette was a 11-36, but even so, it's not clear to me why the feel would be so different between losing those two teeth.

Could you expect in layman's terms why that would be the case?
That is actually strange as generally, most SP bikes are designed to pedal better (more anti-squat) in smaller chain ring combo's than in larger. And honestly, 2 teeth is not alot. If I were to guess, and don't take this personally, it could be a sign of a poor pedal stroke. By spinning a little faster, in too small of a chain-combo, you are activating the suspension by weight shifts.

I actually notice this myself. For example, when I ride my road bike, after a long hiatus, I often feel like I have "pedal bob" when I drop down to too low of a gear. Sounds crazy I know, but is a sign that my pedal stroke is gotten sloppy. There is of course, not "bob" but it feels very similar. And my dw linked bob actually makes me lazy and does not really respond to a bad pedal stroke. In contrast my old SP and HL bikes did.
 
#93 ·
I agree the difference between 28 and 30 is small, but it sounds like 30 is "just right." Going to 28 may have increased or decreased anti-squat, (probably increased), but either way that can increase bob. To much anti squat can cause bob by extending the shock with each stroke.

Also, remember pedal kickback is greater in lower gears (the crank turns more for a given amount of chain length).
 
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