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Running Inserts

Nov. 28, 2019, 5:49 a.m.
Posts: 765
Joined: June 29, 2006

@TAZ123: A tad less lowspeed compression, maybe a tad less rebound. Tire pressure and suspension settings are a tricky problem however.

In my experience, lowish tire pressure feels great for certain types of bumps - it carpets small chatter and hits. The same pressure (with inserts and no snakebites therefore) ridden in rough, rocky conditions can induce severe armpump.

Like with suspension, if you are too far into the travel most of the time and just riding along (too much sag maybe wrong suspension curve) you’ll run into the ramp up too much of the time and therefore the energy will not be dissipated in an even manner, but feel spikey to your arms and body.

Too high a tire pressure will let you bounce and struggle and make you tired fast, too.

Key in reducing rider fatigue seems to be a fitting ratio between the suspension curve of the tire AND the suspension AND the riders strength and dexterity regarding muscles.

Inserts can help with that, because they keep the tire from blowing through their „travel“ (which amounts to a couple of centimeters on a 2.4 tire...). Similar to a short tavel bike which is ridden really hard - with proper suspension settings it won’t be plush, but rideable.

Rim/wheel compliance can have a severe effect under these circumstances, too.

I can reproduce a loud clanging, tire to rim „bang“ event on my front wheel with a stiff 28h Newmen rim on a trail I ride often, but don‘t get the same BANG on either a DT Swiss EX1501 front wheel nor on a Notubes Flow MK3. Same bike, same tire, same pressure, same settings. Just the front wheel is swapped. No inserts. Minion DHF 2.5 WT @21PSI.

I want to nerd out (like you can tell from this post) and verify and reevaluate my findings with a FCK-Flats tire insert in the front tire. What will feel better? Compliant rim without insert or stiff rim with insert?

My (weak-sauce) wrists like extra chunky ESi grips (to filter small stuff) with not too low a tire pressure, firmer but still plush fork and single ply tires with big volume best.

And regarding tubes - I find ride quality AND ease of maintenance AND reliability of a proper tubeless setup is NEXT level compared to tubes. There are certain steps to follow to avoid hassle, for sure. But riding a proper mountain bike with tubes is leaving a lot of performance untouched. If your body can take the punishment of 40PSI and you are happy with the performance - all good for you!


 Last edited by: Znarf on Nov. 28, 2019, 5:54 a.m., edited 1 time in total.
Nov. 28, 2019, 7:27 a.m.
Posts: 14
Joined: Aug. 1, 2019

Posted by: Znarf

@TAZ123: A tad less lowspeed compression, maybe a tad less rebound. Tire pressure and suspension settings are a tricky problem however.

In my experience, lowish tire pressure feels great for certain types of bumps - it carpets small chatter and hits. The same pressure (with inserts and no snakebites therefore) ridden in rough, rocky conditions can induce severe armpump.

Like with suspension, if you are too far into the travel most of the time and just riding along (too much sag maybe wrong suspension curve) you’ll run into the ramp up too much of the time and therefore the energy will not be dissipated in an even manner, but feel spikey to your arms and body.

Too high a tire pressure will let you bounce and struggle and make you tired fast, too.

Key in reducing rider fatigue seems to be a fitting ratio between the suspension curve of the tire AND the suspension AND the riders strength and dexterity regarding muscles.

Inserts can help with that, because they keep the tire from blowing through their „travel“ (which amounts to a couple of centimeters on a 2.4 tire...). Similar to a short tavel bike which is ridden really hard - with proper suspension settings it won’t be plush, but rideable.

Rim/wheel compliance can have a severe effect under these circumstances, too.

I can reproduce a loud clanging, tire to rim „bang“ event on my front wheel with a stiff 28h Newmen rim on a trail I ride often, but don‘t get the same BANG on either a DT Swiss EX1501 front wheel nor on a Notubes Flow MK3. Same bike, same tire, same pressure, same settings. Just the front wheel is swapped. No inserts. Minion DHF 2.5 WT @21PSI.

I want to nerd out (like you can tell from this post) and verify and reevaluate my findings with a FCK-Flats tire insert in the front tire. What will feel better? Compliant rim without insert or stiff rim with insert?

My (weak-sauce) wrists like extra chunky ESi grips (to filter small stuff) with not too low a tire pressure, firmer but still plush fork and single ply tires with big volume best.

And regarding tubes - I find ride quality AND ease of maintenance AND reliability of a proper tubeless setup is NEXT level compared to tubes. There are certain steps to follow to avoid hassle, for sure. But riding a proper mountain bike with tubes is leaving a lot of performance untouched. If your body can take the punishment of 40PSI and you are happy with the performance - all good for you!

Very well said. The difference between a given tire with and without inserts is much like an air sprung fork with and without bottomless tokens - tire inserts and tokens accomplish some of the same things. Tire insert allows you to run lower pressures, allowing more suppleness "off the top" (better traction, comfortable ride). A hard hit causes the air pressure inside the tire to ramp up quicker than in a tire without inserts. Of course, the insert isn't solid plastic, it's closed-cell foam, so there is some compression going on in the insert itself. Definitely takes some trial and error to get your settings right, but well worth it.

Nov. 28, 2019, 3:24 p.m.
Posts: 299
Joined: Nov. 25, 2013

Great insights - thank you. I've had my suspension set up using Arthur (Suspension Therapy), so I have a good baseline to work from. I was trying to visualize how inserts would help/hurt the ride quality, and the token-comment really helps.

Nov. 30, 2019, 7:19 p.m.
Posts: 14
Joined: Aug. 1, 2019

I personally didn't change my suspension settings at all when I installed cush cores.

Dec. 9, 2019, 2:04 a.m.
Posts: 41
Joined: Dec. 1, 2008

Posted by: rwalters

Very well said. The difference between a given tire with and without inserts is much like an air sprung fork with and without bottomless tokens - tire inserts and tokens accomplish some of the same things. Tire insert allows you to run lower pressures, allowing more suppleness "off the top" (better traction, comfortable ride). A hard hit causes the air pressure inside the tire to ramp up quicker than in a tire without inserts. Of course, the insert isn't solid plastic, it's closed-cell foam, so there is some compression going on in the insert itself. Definitely takes some trial and error to get your settings right, but well worth it.

Wouldn't you need to compensate for the lower air volume by increasing tire pressure? Smaller volume ramps up quicker but takes less force to compress in total, just like with narrow tires.

Dec. 9, 2019, 10:38 a.m.
Posts: 877
Joined: June 26, 2012

Posted by: Timer

Wouldn't you need to compensate for the lower air volume by increasing tire pressure? Smaller volume ramps up quicker but takes less force to compress in total, just like with narrow tires.

Except that, at a certain point, the insert starts to compress, and the tire pressure continues to ramp up as that happens.

Dec. 16, 2019, 2:12 p.m.
Posts: 352
Joined: May 11, 2018

To the OP, any feedback on the nukeproof inserts? Was thinking of trying some too.

Dec. 16, 2019, 9:28 p.m.
Posts: 765
Joined: June 29, 2006

I am not the OP, but have been running the Nukeproof ARD for a full season on the rear wheel. They are pretty firm/hard, I wouldn’t expect a lot of extra damping, but they absolutely prevent pinch flats, are easy to mount and unlike Huck Norris or Marshguards FCK Flats they don't have a gazillion of little cuts, holes and punches once I have to swap my tire, because the thread is worn out.

I had a spoke coming loose with them on my rear wheel, which I didn’t have happen the last four seasons with Schwalbe ProCore neither with Marshguards FCK Flats. It were different wheels though and I’d tend to think it was a wheel issue mostly and less the firmer insert.

A couple of friends had to shorten (cut a piece out and reglue) their ARDs, because they grew in diameter and started to rattle pretty awful in the rim/tire. They all used Notubes sealant. I use e*thirteen tire plasma and mine didn’t grow. Coincidence maybe.

The provided tubeless valves didn’t work for most people I spoke to. They wouldn’t seal at the rim/valve hole properly. I use a ghetto valve (round cut out of an old tube) and that works without issue.

Generally I’d recommend them. Value is good.


 Last edited by: Znarf on Dec. 16, 2019, 9:29 p.m., edited 1 time in total.
Dec. 17, 2019, 10:19 a.m.
Posts: 299
Joined: Nov. 25, 2013

It was a bit of a failure.

A few lessons (I echo a number of Znarfs observations). 

- 2.3" Maxxis tires don't like to mount with ARDs on 30mm rims. I think the tires are too narrow.

- The ARD does expand (using Stans). After fighting the tire-fight for a good hour (and breaking 3 tire levers), I gave up on the first night. When I came back the following evening to finish it off, the ARD had expanded (I use Stans), so I will need to cut them and re-connect/glue them back together.

- The included valves are useless (very small opening) - I have Raceface Turbine wheels that are asymmetrical - so a wedge spacer is needed to get a proper seal (don't forget this part). I may try them again with a compressor... A regular tubeless valve will push air directly into the insert...so I'm not sure of the solution here.

- In the end, I gave up and mounted a new Onza tire (2.4" with a wider tread pattern) without an insert. Side-note, not a bad tire (IBEX) - very similar to the Maxxis Highroller II WT.

- I will cut them down over the holidays and try again (may need a few extra beers for stress management), and hopefully I can get them to seat with a compressor. I don't see them seating by hand, but I will try again with a regular tubeless valve. This makes me think that the trail-side repair is to pull the insert and install a tube and wear a lovely yellow sash (i.e. the ARD).

-Gord

Dec. 17, 2019, 2:08 p.m.
Posts: 75
Joined: April 26, 2004

I have been using Pepi's Rokline Noodles (the yellow/enduro ones, not the red/Race ones) mainly with 2.25 Racing Ralph but lately a 2.35 Nobby Nic, both with 22mm ID rims (narrow rims are super cheap these days).

The noodle compresses into the narrow rim and uses up almost all the lateral space inside the tire, so laterally the tire is supported as if it has greater than 30 psi in it; however, vertically (for at least10 mm) the tire is very soft and feels like what ever your pressure gauge says it should feel like.

At first I was having trouble getting the rim-tape to stick, so had multiple times to test the run-flat capabilities (no damage to rim, tire or noodle after riding out a downhill trail + 5km of pavement at 0 psi to get home). The noodle locks the bead to the rim (providing you are not racing World Cup DH), so it is just easier to deal with the flat when you get home rather than trying to fix on a trail.

That first 10 or so mm of vertical travel makes a small tire feel like a fat tire when riding over chunky rail ballast (but still accelerates and is agile like a small tire). Much less rolling resistance over chunky stuff and I can't feel much if any difference on pavement.

Typically I run 5psi less than non-insert pressures.


 Last edited by: taprider on Dec. 17, 2019, 2:10 p.m., edited 1 time in total.
Dec. 18, 2019, 12:16 p.m.
Posts: 765
Joined: June 29, 2006

I actually didn’t have trouble installing the ARD and tire on DT EX511 rims, Bontrager Line COMP and Notubes FLOW MK3 rims with 2.4 WT Maxxis tires. All are roughly 30mm iw

It even worked relatively straight forward with a 2.3 DHR2.

It’s absolutely helpful if you have a second pair of hands keeping the tire bead in the middle channel and it is an absolute must to start mounting the bead OPPOSITE to the valve.

But I can absolutely imagine how that asymmetric rim channel could make for a messy beer related rim job!


 Last edited by: Znarf on Dec. 18, 2019, 12:16 p.m., edited 1 time in total.

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