COG for new TiLIte

[reaton]

Hello All,

My new TiLite ZRA chair with ergo seating was delivered yesterday and I am in the adjusting and breaking in stage. In my old TiLite chair I had 3.5 inch COG because I like a tippy chair. Due to the ergo seating I could only get 3 inches of COG max....I miss that extra 1/2 inch of COG. Does anyone have any tips or advice how I could get another 1/2 inch or at least make me feel like I am getting
another 1/2 inch of COG ?

-Ronnie

[Patrick Madsen]

One way is too tilt the back rearward a few degrees.

[Oddity]

Can you flip the camber tube clamps around to face the other direction? Sometimes that'll squeeze a little more out of it, if they're facing toward the rear to begin with.

Edit: sorry was thinking of the ZR clamps. The ZRA is different. Might still be possible though. If you look at section 8-2, 3 of the ZRA manual, it looks like a simple thing to remove the Camber Mount Clamp and flip the whole camber tube and axle plate assembly around so the Camber Tube is in front of the Camber Clamp instead of behind it. That'd add at least an inch or two it looks like. Then you could adjust it back a bit to where you like it.
https://permobilus.com/wp-content/up...-Z_ZRA_Web.pdf


Might also be able to slack the back upholstery off a bit to sit deeper.

[August West]

You can add backward tippiness by increasing dump as follows: 1) lower the rear seat height, 2) raise the front seat height with taller forks, 3) raise the front seat height with larger caster, or 4) raise the front seat height by moving the caster axles to the lower hole on the fork. Of course, you can only do this if the axle is presently on the top hole of the fork. If your fork doesn't have two holes, you may drill a new hole.

You may want to move the back angle forward in order to compensate for the increased dump.

[Oddity]

Solutions that require changing your prescribed seating position are less than ideal, IMO. That will create changes in joint angles, posture, and pressure distribution. I'd just flip the camber tube around, keeping everything else the same, if it were mine. I've checked on my TiLite that uses the same axle plate and camber clamps and it'd be easy.

[August West]

Agreed. I'd take the easier solution as well. But, other alternatives are available.

BTW, "prescribed seating position"? Don't get me started. They really messed me up good with my seating position. Sitting too high for 5+ years ruined my shoulders. My new chair has me sitting lower (by my own prescription) and my shoulders are gradually making a comeback. I would have gone to an early grave waiting on them to figure it out.

I know this is where you say just because one therapist was inept doesn't mean all others are. True. But it's still good to be the one who knows you best.

[Oddity]

Yeah. Good seating therapists are hard to find it seems. Giving advice on stuff like that over the interwebnets is tough, too. I feel a certain amount of 'personal liability' that pushes me to say stuff like that. The idea of someone getting a sore off of my advice is sobering. But, I configured all my chairs but the first, too!

[August West]

Point well taken. But he asked for tips and I offered ideas not recommendations. Isn't that one large reason we're here, to share experiences and ideas?

As long as we're on the subject, a seating therapist will recommend your knees be placed below your hips. Stuff will fall out of your lap that way. It's easier to carry stuff on your lap with your knees higher (more dump). It also makes you more stable while you push and reach.

The downside is potential for sores. That happened to me from too much dump in a Jay cushion. I can't say if it was due to dump or the Jay cushion, probably a combination of both, The jell in Jay cushions bunches from the get-go (first time you bend) to the point that it's not doing any good and you're bottoming out. Luckily, skin didn't split open. But definitely more pressure than a therapist would recommend. It's all trade off between function vs care.

[reaton]

Oddity - what a great idea you have about reversing the camber tube clamps around. Looking at my chair I don't see why this cannot be done.

August - yes, I am going to try raising my castor in the first hole of the fork and see if that gives me the tipsiness I am looking for.

Thank you both.

-Ronnie

[Patrick Madsen]

Oddity - what a great idea you have about reversing the camber tube clamps around. Looking at my chair I don't see why this cannot be done.

August - yes, I am going to try raising my castor in the first hole of the fork and see if that gives me the tipsiness I am looking for.

Thank you both.

-Ronnie

Raising your casters only will put the front wheels off 90o so would have to adjust the front barrel housing to be 90o .

[Oddity]

Raising your casters only will put the front wheels off 90o so would have to adjust the front barrel housing to be 90o .

Ronnie,
If you're not familiar with what this means, at the factory they make sure the vertical axis of the fork is perfectly perpendicular to the floor, so when the fork rotates around 360deg the front seat height doesn't change a bit. In addition to feeling a little 'bump' during fork rotation when the caster goes from leading to trailing (the seat height changing a bit), it can also cause caster flutter and premature beating failure (since the pressure isn't even on the fork stem bearings anymore.)

The manual I linked earlier has detailed instructions on how to square the casters in section 11-6, 7.

Its kind of a pain in the ass.

You could avoid the need by simply adjusting the backrest to a more open angle, the angle it would be at if you raised the front using the caster holes. It's not ideal or exactly the same but might be much easier to deal with.

[Patrick Madsen]

Agre with Oddity, Its a pain to adjust the front caster to be the same. Easier to open the bank andgle a bit.

[August West]

Raising your casters only will put the front wheels off 90o so would have to adjust the front barrel housing to be 90o .

I have increased dump by 1/2" without adjusting caster angle. It's not the ideal 90 angle but I didn't find a difference in turning. But I like to keep it 90 degrees just because. Not sure why you call it a pain. On my TRA, it's just loosening a bolt, adjusting the caster angle, and tightening the bolt.

[Oddity]

It depends on the chair. This one might not be too bad. I've always had to break out the carpenter's square and get it up on a table to fiddle with it to get it exact. Eyeballing it is fine I goes but if I'm breaking out tools imma do it as perfect as I can manage. Relative to tweaking the back angle (especially with the new TiLite adjustable hardware) its a pain. (Btw they still haven't updated the manuals with the new backrest hardware. They should. In case they're lurking...hint hint.)

[August West]

I understand. If the adjustment is infinitesimal then you could spend a lot of time on it if you're a perfectionist. But I don't think it's that way on my chair. if I recall correctly, it's a tooth and groove design. Hence, you select the one position that is closest to 90 degrees. May not be as accurate as if you squared it with a tool. But it's much faster, easier, and probably no significant difference.

I hit a pothole that sent my fork out of alignment so I have to adjust it back to normal. I'll report back what I find and try to take some pictures if feasible.