Lowering the suspension AER 48

[snydes]

It’s a long shot but I figured I’d ask. The mrs. needs her suspension set up and lowered for her small stature, but this is the absolute busiest time of the year to do so and we have a bunch of rides coming up we were hoping to not miss. @OneLapper hooked me up with a shock to use so I was able to get that sent out awhile, but the forks are likely going to have to wait unless one of you guys had a set you wouldn’t mind loaning out.

Thanks!

 

[OneLapper]

Same seller I got that shock off of.

KTM 250 SXF 2015 Forks WP 4CS 48mm 125 350 450 525 SX SXF Husky ALTA Redshift | eBay

No one wants to spend that much on a temp suspension, but I didn't find 4CS forks on ebay for cheaper.......

 

[wildman240]

Same seller I got that shock off of.

KTM 250 SXF 2015 Forks WP 4CS 48mm 125 350 450 525 SX SXF Husky ALTA Redshift | eBay

No one wants to spend that much on a temp suspension, but I didn't find 4CS forks on ebay for cheaper.......

I've purchased a few things from him too.

 

[snydes]

Yeah, I think we will be waiting until fall to do the forks!

 

[snydes]

Just to follow up and for future reference, I ended up purchasing an eBay set of AER inner cartridges to lower/modify. The AER’s you have to shorten the damper rod on the air side to properly lower. The dampening side you can either shorten the same way or (to the best of my knowledge) use a traditional travel limiting spacer. Worst case if you only shorten the air side, and you want to return it to stock you would have to replace that damper rod at approximately $150.

Here is a brief video explaining the damper rod modification;

The shock can also be lowered with traditional travel limiting spacers.

Thanks to @Tuner for some guidance on what needed to be done with these!

 

[Philip]

Can you just add spacers on the air side and grind a new air pressure balancing port?

 

[snydes]

That port is pressed into the tube, and there is a raised rib on the outside. Chances are if you were able to access the inside of the tube well enough to grind a precise groove, you would have ground the tube paper thin. Also, the tube is likely more money to replace in the event you wanted to return the suspension to stock height.

@Mark911 had a interesting idea for a custom made lowering seal head that wouldn’t require cutting anything, but I ended up cutting and rethreading the rod.

 

[zootie]

Just to follow up and for future reference, I ended up purchasing an eBay set of AER inner cartridges to lower/modify. The AER’s you have to shorten the damper rod on the air side to properly lower. The dampening side you can either shorten the same way or (to the best of my knowledge) use a traditional travel limiting spacer. Worst case if you only shorten the air side, and you want to return it to stock you would have to replace that damper rod at approximately $150.

Here is a brief video explaining the damper rod modification;

The shock can also be lowered with traditional travel limiting spacers.

Thanks to @Tuner for some guidance on what needed to be done with these!

will lowering the forks affect the quick turning the Alta has in stock?

 

[snydes]

will lowering the forks affect the quick turning the Alta has in stock?

As long as the whole suspension is lowered together the same amount, the steering angle will remain the same so it should feel identical in that respect.

 

[zootie]

As long as the whole suspension is lowered together the same amount, the steering angle will remain the same so it should feel identical in that respect.

Thank you!

 

[Tuner]

will lowering the forks affect the quick turning the Alta has in stock?

Lowering the motorcycle will lower the CG which will increase the steering effort for a given turn radius / lean angle.

 

[mrs. snydes]

will lowering the forks affect the quick turning the Alta has in stock?

will lowering the forks affect the quick turning the Alta has in stock?

I’ve ridden my Alta both stock and with a lowered suspension. I haven’t seen a noticeable difference in the bike’s turning characteristics. I have seen an improvement in my willingness to attack a turn now that I can somewhat touch.

 

[Tuner]

I’ve ridden my Alta both stock and with a lowered suspension. I haven’t seen a noticeable difference in the bike’s turning characteristics. I have seen an improvement in my willingness to attack a turn now that I can somewhat touch.

Confidence is paramount. Oftentimes being able to touch the ground flat footed makes all the difference in the world. With exception of Flat Track specific applications, suspension lowering is most often implemented to enhance rider confidence via being able to easily touch the ground. That said, a lower CG and all else remaining equal, will increase stability along with steering effort. Please keep in mind that CG is simply one of many variables that impact the overall feel of a motorcycle. Motorcycle riding is dynamic and no single setting will be perfect for every condition and preference. Glad that lowering your suspension netted the results that you were seeking. All the best, Dale

 

[mrs. snydes]

Confidence is paramount. Oftentimes being able to touch the ground flat footed makes all the difference in the world. With exception of Flat Track specific applications, suspension lowering is most often implemented to enhance rider confidence via being able to easily touch the ground. That said, a lower CG and all else remaining equal, will increase stability along with steering effort. Please keep in mind that CG is simply one of many variables that impact the overall feel of a motorcycle. Motorcycle riding is dynamic and no single setting will be perfect for every condition and preference. Glad that lowering your suspension netted the results that you were seeking. All the best, Dale

Flat footed is a dream. I can touch on my very tippy toes almost now that it’s lowered Short girl problems. Lol. I like the lower cg but when you’re really short a high cg might feel different in proportion to a tall rider.

 

[Tuner]

Flat footed is a dream. I can touch on my very tippy toes almost now that it’s lowered Short girl problems. Lol. I like the lower cg but when you’re really short a high cg might feel different in proportion to a tall rider.

Absolutely! As a rider you are part of the dynamic CG equation. Shorter rider = lower CG. Perception is objective. Physics is physics. That said, one man / woman's utopia is another's Hell. Such is what makes chassis / suspension tuning a challenging, yet rewarding venture.

 

[Philip]

That said, a lower CG and all else remaining equal, will increase stability along with steering effort.

Dale, could you please explain why that is so?

 

[Tuner]

Dale, could you please explain why that is so?

In a word, Leverage. Place a weight on the end of a pencil. Now place the pencil weighted end down. Note that the pencil wants to stand vertical. Now place the non weighted end down. Unless perfectly balanced, the pencil now wants to tip. Remember.... " Weebles Wobble But They Don't Fall Down "

 

[snydes]

I like that analogy. I would imagine that in the case of throwing a dirt bike down into a berm/turn having the CG higher would work to your advantage to a certain degree. I could be looking at it wrong though!

Good discussion!

 

[Philip]

I am not following the analogy, but "leverage" is the correct word. It takes less effort to steer the front wheel and lean the bike if the distance from the contact patch to the roll axis is longer -- a larger lever.

This probably is the case only in turns entries and exits. Or when entering and exiting berms. In the middle of a berm the steering effort could be zero, theoretically. And, when we are done leaning the bike, and do not need to make steering corrections, the efforts should not depend on the CG height anymore.

 

[Tuner]

I am not following the analogy, but "leverage" is the correct word. It takes less effort to steer the front wheel and lean the bike if the distance from the contact patch to the roll axis is longer -- a larger lever.

This probably is the case only in turns entries and exits. Or when entering and exiting berms. In the middle of a berm the steering effort could be zero, theoretically. And, when we are done leaning the bike, and do not need to make steering corrections, the efforts should not depend on the CG height anymore.

The pencil weighted end down has the CG near the contact patch. Weighted end up moves the CG away from the contact patch. Forces acting through the weight are increased as a result of the increased lever ratio. During a turn gravity wants to lean the bike inward while centrifugal forces attempt to stand it up. The further the CG from the contact patch, the greater the force.