Any Experience With Ti Softail?

[Freediver]

The first and third options still have a conventional shock absorber, the "soft tail" part really just uses flex points to replace pivots.

The other options like the Moots YBB offered different elastomers from memory...?

I always figured the chainstays acted like a spring. I've never ridden one if you can't tell.

 

[beeb]

I always figured the chainstays acted like a spring. I've never ridden one if you can't tell.

Nor have I, but if you sat my 90+kg on the end of a 435mm long bar it's going to need more than two narrow strips of 4mm think Ti to support it... Hence the flex point is really closer to "spring assisted" pivot than a complete spring.

XC/"downcountry" bikes with flex stays also have inherent spring in the rear triangle as it spreads/contracts during the suspension cycle, but it's insignificant to the mass/force applied by the rider so they still have a shock for the same reason.

 

[Shorsau]

@Shorsau - Technically speaking, if you wanted something with flex points like the first and third frames picture but on a frame with a Pinion gearbox mount, it might work out alright. Because the Pinion mount cradle is effectively the lowest point of the front triangle, if the flex point was mounted up off the back of the cradle the belt/chain forces would be much closer to neutral (assuming a chainring/cog roughly equivalent in radius to the height of the mount cradle attachement). Depending on the positioning of the flex point you might even be able to introduce some anti-squat - how little/how much would be a hard one to judge though given the spring force of the flex point is pretty much an unknown (unless you have access to the frame drawing, and CAD/FEA programs). And then you have to try and explain/translate to the builders and then convince them to do something other than their bog-stock designs (good luck!).

Now I want to build one, lol.

Well that piques my interest for sure @beeb. From reading a bit on forums, the manufacturers seem to use either 6 or 8mm plate..the one from Titan used 6mm and he gets quite a bit of flex out of it going by the video on the page below. I'd probably ask Waltly about 8mm.

Softail titanium MTB 29/27.5+ (all mountain - bikepacking)

Softail titanium MTB 29/27.5+ (all mountain - bikepacking)

chinertown.com

 

[beeb]

Well that piques my interest for sure @beeb. From reading a bit on forums, the manufacturers seem to use either 6 or 8mm plate..the one from Titan used 6mm and he gets quite a bit of flex out of it going by the video on the page below. I'd probably ask Waltly about 8mm.

Softail titanium MTB 29/27.5+ (all mountain - bikepacking)

Softail titanium MTB 29/27.5+ (all mountain - bikepacking)

chinertown.com

Erm, what post is the video/link in? I'm seeing lots'o'text and some pictures...

 

[Shorsau]

Erm, what post is the video/link in? I'm seeing lots'o'text and some pictures...

Sorry..is hidden among the text

Watch VIDEO_20210516_094533 | Streamable

Watch "VIDEO_20210516_094533" on Streamable.

streamable.com

 

[beeb]

Sorry..is hidden among the text

Watch VIDEO_20210516_094533 | Streamable

Watch "VIDEO_20210516_094533" on Streamable.

streamable.com

Thank you.

...the manufacturers seem to use either 6 or 8mm plate..the one from Titan used 6mm and he gets quite a bit of flex out of it going by the video on the page below. I'd probably ask Waltly about 8mm.

Interesting that they use such thick plate. Personally I'd err towards the thinner end. My logic being that having less stress applied to the welds in the frame would be preferable and you still have the shock (air or coil sprung) to tune the support.

Interesting how much the shock mount on the 'seatstay' in that video deflects away from the shock mount without the shock in position to align it with the mount. Even with the flex-stays in the seat stay near the rear axle that must cause a hell of a lot of side loading (well, vertical loading) on the shock shaft. I'd try to get a upper linkage in place instead of the seat stays driving straight into the shock and the shock having to locate it all.

It'd really be worth having a look at Linkage X3 so you could come up with a kinematic with relatively 'known' values (It's worth getting the paid version that shows you the values on the graphs). It won't account for a flex point instead of a pivot, but if you place the pivots roughly where the centre of the flex point is it should at least let you get an impression of how various changes to pivot placement or linkages would effect the kinematic.

 

[Shorsau]

Thank you.


Interesting that they use such thick plate. Personally I'd err towards the thinner end. My logic being that having less stress applied to the welds in the frame would be preferable and you still have the shock (air or coil sprung) to tune the support.

Interesting how much the shock mount on the 'seatstay' in that video deflects away from the shock mount without the shock in position to align it with the mount. Even with the flex-stays in the seat stay near the rear axle that must cause a hell of a lot of side loading (well, vertical loading) on the shock shaft. I'd try to get a upper linkage in place instead of the seat stays driving straight into the shock and the shock having to locate it all.

It'd really be worth having a look at Linkage X3 so you could come up with a kinematic with relatively 'known' values (It's worth getting the paid version that shows you the values on the graphs). It won't account for a flex point instead of a pivot, but if you place the pivots roughly where the centre of the flex point is it should at least let you get an impression of how various changes to pivot placement or linkages would effect the kinematic.

So by thinner you would look at the 6mm yeah? This is all new ground for me @beeb, so will get onto Linkage X3 to try and understand a bit more about it Mate. Wish me luck

 

[beeb]

So by thinner you would look at the 6mm yeah?

It's just IMO, but yes - that's what I'd do. About the only spot Ti frames seem to crack is near welds, so I imagine minimise twisting/flexing force at the flex member's attaching welds would be preferable. Call it an educated hunch.

Good luck.

 

[Shorsau]

It's just IMO, but yes - that's what I'd do. About the only spot Ti frames seem to crack is near welds, so I imagine minimise twisting/flexing force at the flex member's attaching welds would be preferable. Call it an educated hunch.

Good luck.

Thanks @beeb..will let you know how I get on

 

[Shorsau]

Thank you.


Interesting that they use such thick plate. Personally I'd err towards the thinner end. My logic being that having less stress applied to the welds in the frame would be preferable and you still have the shock (air or coil sprung) to tune the support.

Interesting how much the shock mount on the 'seatstay' in that video deflects away from the shock mount without the shock in position to align it with the mount. Even with the flex-stays in the seat stay near the rear axle that must cause a hell of a lot of side loading (well, vertical loading) on the shock shaft. I'd try to get a upper linkage in place instead of the seat stays driving straight into the shock and the shock having to locate it all.

It'd really be worth having a look at Linkage X3 so you could come up with a kinematic with relatively 'known' values (It's worth getting the paid version that shows you the values on the graphs). It won't account for a flex point instead of a pivot, but if you place the pivots roughly where the centre of the flex point is it should at least let you get an impression of how various changes to pivot placement or linkages would effect the kinematic.

I just saw this on the Waltly Alibaba site, looks like a better design.

 

[Calvin27]

My 2c not a fan of flex designs. The material is the least of your worries, Ti and carbon have very good fatigue properties, heck even the giant stance in alloy uses a flex point design and I haven't heard any horro stories from that bike. The main point of failure is going to be the welds imo.

Personally I rekon there is too much going on and not that much of an advantage. You still have a shock to maintain, the suspension won't be as good as a 4 bar (or even a single pivot), and you don't get the benefits of s short chainstay because of the pinion.

Having said that I do want to build a soft tail myself in Ti, but without the shock and pinion. Might go for a rohloff or alternative hub gear.

 

[Shorsau]

I'd love to ride a bike with a Kindernay hub to see what the hyd shifting was like..they are a bit more expensive than Pinion, but can use between bikes or even different wheel sizes if you purchase extra swap cages.

 

[Calvin27]

I'd love to ride a bike with a Kindernay hub to see what the hyd shifting was like..they are a bit more expensive than Pinion, but can use between bikes or even different wheel sizes if you purchase extra swap cages.

Everyything is a bit of a compromise. I have ridden two hub gears - a flat bar and a mtb and while it's ok for commuting, any sort of agility is noticably munted due to the massive weight at the rear.

Pinions are the nicer option but stupidly expensive. I have ridden some mid drives and they do feel nicer but crazy expensive. I don't understand how a bafang ebike mid drive costs a fraction of a pinion gearbox. Probably germany tax, but if there was a cheaper alternative gearbox I'd go for that.

Back on topic though, you should probably think about what you are trying to achieve. We all have bike pipe dreams i am sooo guilty of this, but when you sit down and plan and work it out sometimes it doesn't make sense and that's fine and all part of the fun.

 

[Shorsau]

Everyything is a bit of a compromise. I have ridden two hub gears - a flat bar and a mtb and while it's ok for commuting, any sort of agility is noticably munted due to the massive weight at the rear.

Pinions are the nicer option but stupidly expensive. I have ridden some mid drives and they do feel nicer but crazy expensive. I don't understand how a bafang ebike mid drive costs a fraction of a pinion gearbox. Probably germany tax, but if there was a cheaper alternative gearbox I'd go for that.

Back on topic though, you should probably think about what you are trying to achieve. We all have bike pipe dreams i am sooo guilty of this, but when you sit down and plan and work it out sometimes it doesn't make sense and that's fine and all part of the fun.

Pinion prices have become a lot more reasonably priced with the introduction of the C line, the link below is for their online shop. I do realise that my planning is all pie in the sky stuff at the moment, but it's something to fill the day with

What design were you thinking of for your Ti softail?

Pinion Ersatzteile - Getriebe | pinion-bikes.com

Hochwertige Pinion-Ersatzteile für Fahrradgetriebe aller Art bei bike-prof.de

pinion-bikes.de

 

[Calvin27]

What design were you thinking of for your Ti softail?

https://pinion-bikes.de/Getriebe

Pinion belt drive, with lauf up front. The idea is a softly sprung rig, possibly 50mm elastomer + flex stays, can be used for XC, bikepacking and commute without the maintenance of shocks or chains. Basically want to be able to ride this for a year without so much more than glancing at a brake pad to assess wear.

Very pipe dream though. Have too many bikes in the shed and it was all fun and games but rate rises has had the intended effect on me for now

 

[Shorsau]

Pinion belt drive, with lauf up front. The idea is a softly sprung rig, possibly 50mm elastomer + flex stays, can be used for XC, bikepacking and commute without the maintenance of shocks or chains. Basically want to be able to ride this for a year without so much more than glancing at a brake pad to assess wear.

Very pipe dream though. Have too many bikes in the shed and it was all fun and games but rate rises has had the intended effect on me for now

Hearing you on that..I might get a Thudbuster for the time being on this one and see how much of a difference that makes.

 

[Calvin27]

Thudbuster for the time being on this one and see how much of a difference that makes.

Nah that bike is not what you need .... sell it and start again, what size are you again?

 

[Shorsau]

Nah that bike is not what you need .... sell it and start again, what size are you again?

Big..too big