Progressive vs linear

[Vtamb81]

I know this is a wide topic and I’ve been reading lots of resources online...and I know frequently the answer is “it depends”. I’m going to attempt to be very clear in my question(s) and hope the people with extensive suspension experience can weigh in ( @Ktmmitch, @Suspension101@Camel ADV and others). Posts like this have me thinking about how best to address my fork upgrades. 

I currently don’t have the resources to fully swap my fork internals, and looking to start with just a spring upgrade. I’m thinking about pairing a progressive fork spring with an already installed RR linear rear spring given the rear linkage is considered pretty progressive (?). 
 

Problem: I am an intermediate rider (215 lbs in riding gear) and always looking to advance. The fork problems I’m attempting to address is significant fork dive at the top of the stroke under braking and moderate off road hits and frequent bottoming out based on my riding style. The rear has been transformed in a very positive way by the 90nm spring. A few times a year I also carry ~30 lbs of luggage for longer rides. 

1. What should I be considering when deciding between a progressive (like HyperPro 6-9nm spring) or a linear fork spring (recommended 6.4nm by RaceTech)?

 

2. Should I be concerned about pairing a linear rear spring and progressive fork spring. 
 

3. Does a progressive spring have a greater potential to solve the performance concerned I outlined?

 

Really appreciate any insight. 
 

Aaron

Edited September 13, 2020 by Vtamb81

[Suspension101]

Forks: The biggest reason manufacturers changed the design of the forks from the old school orifice damper rod fork is to reduce the progressive nature of the forks. They had so much progression in a high speed event that they were very harsh.

So they went to a more expensive shim stack style fork that is much more linear without the progressive spike.

If you never intend to modify the fork internals then I think you could get improvement from a progressive spring. Would have to test to confirm. You would be as they say, be riding the spring, as it would be with light damping. This can well be an improvement from stock but will not have the control and steadiness of a properly sprung and damped system. I do not use progressive fork springs as I want the balanced system damping/spring. A proper straight rate with proper pre-load is quite an improvement with room to make it even better.

Shock: Different animal all together. Variable rate spring gives much more weight range when you add or delete bags etc. The shock is a 2 to 1 ratio thank you @camel ADV as he did the ratio measurement. That is a lot of damping needed for a 40mm shock so the variable can be a big help to keep it from going so deep in the stoke without creating too much cavitation. This also makes it easier to control the rebound because your not going so deep. Plus variables tend to start softer than rated, helping with initial strike harshness. Kind of like a straight rate fork spring with light preload does.

 

Two different rate springs in a fork is perfectly fine and we do it often for the pro riders and not so often with the weekend warrior simply because they are wary of it.

 

Greater potential?  That would take some time to ascertain but I am quite sure I could make the fork straight rate out perform the fork progressive for the reasons mentioned above.

On my website videos, we are making more next week by the way. All the bikes on my website have progressive rear springs and straight rate fork springs. Big bikes and small alike.

 

Straight rate is my vote and one of the members here just emailed me a couple days ago his satisfaction with straight up front and variable out back. His words, more controlled, more bottoming resistance, more compliant more plush.

Edited September 13, 2020 by Suspension101

[Vtamb81]

George, I really appreciate the feedback and it makes a lot of sense to me. Even though my resources are limiting my fork work to springs/preload adjustment right now, it is my intention to do a proper valve update in the future. 
 

Taking that into consideration, it sounds like properly sprung linear springs are the way to go. 

Edited September 13, 2020 by Vtamb81

[Camel ADV]

11 hours ago, Vtamb81 said:

I know this is a wide topic and I’ve been reading lots of resources online...and I know frequently the answer is “it depends”. I’m going to attempt to be very clear in my question(s) and hope the people with extensive suspension experience can weigh in ( @Ktmmitch, @Suspension101@Camel ADV and others). Posts like this have me thinking about how best to address my fork upgrades. 

I currently don’t have the resources to fully swap my fork internals, and looking to start with just a spring upgrade. I’m thinking about pairing a progressive fork spring with an already installed RR linear rear spring given the rear linkage is considered pretty progressive (?). 
 

Problem: I am an intermediate rider (215 lbs in riding gear) and always looking to advance. The fork problems I’m attempting to address is significant fork dive at the top of the stroke under braking and moderate off road hits and frequent bottoming out based on my riding style. The rear has been transformed in a very positive way by the 90nm spring. A few times a year I also carry ~30 lbs of luggage for longer rides. 

1. What should I be considering when deciding between a progressive (like HyperPro 6-9nm spring) or a linear fork spring (recommended 6.4nm by RaceTech)?

 

2. Should I be concerned about pairing a linear rear spring and progressive fork spring. 
 

3. Does a progressive spring have a greater potential to solve the performance concerned I outlined?

 

Really appreciate any insight. 
 

Aaron

Thanks for the mention but I'm no suspension expert, I just happen to know a couple (including George  @Suspension101)!