WholeGrain Cycles Jack Rack Kickstarter

[Richpips]

I saw this awhile ago https://bikepacking.com/news/wholegrain-cycles-jack/

I signed up for emails, and it looks like it goes live tomorrow.

This preview may or may not work for you - https://www.kickstarter.com/projects/mi ... n=aefcc894

What do you think?

[ssnowman]

I saw this awhile ago https://bikepacking.com/news/wholegrain-cycles-jack/

I signed up for emails, and it looks like it goes live tomorrow.

This preview may or may not work for you - https://www.kickstarter.com/projects/mi ... n=aefcc894

What do you think?

Looks impressive. I like how easy it is to install and remove.

[woodsmith]

I can't see the straps being able to hold it firmly enough to stop it bouncing around with off-road use. Weighs quite a bit more than my Salsa minimalist rack too.

[slarge]

I predict regular breakages at the bottom of the little plastic bracket below the bars.

Stainless fatigue strength is not good, and all the weight is in the wrong place for that mounting system - lots of strength could be added by a support at the bottom to the fork crown........

[thenorthwind]

The strap holding it to the top of the steerer would be a lot more effective if it were round the fork crown. It would be more effective again if it were somehow made rigid so it resisted compression as well as tension, which would relieve some of the stress on the bit under the stem.

That said, I like the design, and looking at the designers' replies to some of the comments on that Bikepacking.com article, a lot of thought has gone into it and efforts to keep it simple, which is wise.

[jameso]

I like that. I made something similar to that (though simpler, by skill limits more than by design) inspired by the Nitto bar bag support. It's for my roadpacker, to go with a 3-4l bag I have and it works well. Maybe not the solution for real MTB riding but great for road and byways. Ridden across France N-S 2x and 2 TNRs on it plus other shorter rides. It's 1/5th of the weight of this but also only works with one bag type.

304 stainless is lower UTS than CrMo but not something that should stop the design being durable, just makes it heavier? 500g seems reassuring. Powder or plasti-coated CrMo may be lighter if you could get tubes in the right sizes but stainless does look good.

If they've done their testing I wouldn't be too concerned about the durability, the whole thing could be like a spring. It looks like it can take a big bag and people will overload bags but for the 2-3kg I'd put in a road bar bag, I'd be interested to try one.

The strap holding it to the top of the steerer would be a lot more effective if it were round the fork crown.

- it would then flex differently though, that may not be how they wanted it to work? I'm a fan of the idea of racks that can flex and suspend the load to some extent.

[thenorthwind]

The strap holding it to the top of the steerer would be a lot more effective if it were round the fork crown.

- it would then flex differently though, that may not be how they wanted it to work? I'm a fan of the idea of racks that can flex and suspend the load to some extent.

Yeah, fair point. I was more thinking about it moving around than it breaking, but having now seen the fitting video on the Kickstarter I can better see how it works, and am more convinced that it won't move excessively. It's going to flex a bit with a few kilos on it, but as you say, perhaps that's not a bad thing. A lower strap would increase its lifetime, but we might be talking the difference between 10^6 hours and 10^5 hours (numbers picked out of thin air), i.e. irrelevant practically.

With your experience James, what are your thoughts on using solid bar instead of tube?

[TheBrownDog]

I like it heaps. Time will tell if it's robust enough but a weight limit of 5kg, which is far more than even I carry on my bars, sounds like it's built for endurance.

But, James, have you invented a new thing? Roadpacking? What have I missed?

It's for my roadpacker

[Bearbonesnorm]

With your experience James, what are your thoughts on using solid bar instead of tube?

As a rule, solid will be over twice the weight but offer very little increase in strength.

[jameso]

But, James, have you invented a new thing? Roadpacking? What have I missed?

It's for my roadpacker

It's a lot like touring with light kit ; ) so, like bikepacking, but if I'm on road some* might say I'm not bikepacking.
The alternative to roadpacking may be dirtpacking, which is ok as long as you think dirtbagging when you hear either. Roadbagging? Col bagging while dirtbag bikepacking?
Just a load of words and waffle isn't it :)

*No one

[jameso]

With your experience James, what are your thoughts on using solid bar instead of tube?

I've no experience with solid bar :) I designed one front rack that overcame some of the risks in common designs but that's all. Generally tubes are more effective use of materials aren't they, but also there's the basic idea that you add diameter for stiffness but add wall thickness for toughness. Does that work as far as a bar? Springs use bar not tubes, no tubular springs as far as I'm aware but that may be more about manufacturing reality than an engineering ideal?

[Bearbonesnorm]

Springs use bar not tubes, no tubular springs as far as I'm aware but that may be more about manufacturing reality than an engineering ideal?

A spring is subjected to different forces / stresses than a rack, frame etc though.

[jameso]

Springs use bar not tubes, no tubular springs as far as I'm aware but that may be more about manufacturing reality than an engineering ideal?

A spring is subjected to different forces / stresses than a rack, frame etc though.

Sure, different stiffness:weight needs plus the bending range in a spring is greater than you'd get in a frame, plus things I will have missed. The bar OD wouldn't be as easy to make as a tube then form but it could be done. Just thinking how there are Ti springs available to drop weight on bikes but not tubular steel, then how a springy rack might be best engineered - if this rack actually is springy and if you'd actually want much spring before it becomes detrimental. I was thinking abut any obvious mechanical reasons not to use a tube for a spring if it could be formed, the OD may have to go up a bit to make it worthwhile (stiffness:weight) and then you're into coil-binding for a given spring and compression length. Digressing... What I want is an elastomer-suspended rack that weighs <200g

[Dyffers]

https://www.kickstarter.com/projects/mi ... n=aefcc894

What do you think?

No comment on the rack, but if I had taken the money I've put into a handful of Kickstarter projects over the years and set fire to it I would have got more back from my investments.

So, how good is a rack that you pay for but never receive? At least it will never break.

[Ray Young]

https://bikepacking.com/gear/jack-bike-rack-review/

[ScotRoutes]

Good review. I'd wondered about carrying a packraft on it.

[fatbikephil]

Hmmm. Dunno really, I kind of thing that if you are running springers your as well using a bar roll or harness. If you have rigids, bolt something to them solidly. Mixing a steel rack with straps seems to get the worst of all worlds - potential for it to break but not being solidly mounted to the bike so subject to bouncing and bending as well as damaging bars from the resulting rub.

Re tube versus solid, delving deep into the darkest recesses of my aging and deteriorating brain, I recall that a 'tube' with an ID about 2-5% of the OD was stronger than a solid bar of the same OD as the hole allows stresses to be relived around the internal tube. I think (errr) that a tube of a certain dia is 'stronger' than a solid bar of a lesser dia but with the same cross sectional area of metal. I suspect there is a way of calculating all of that but that kind of thing long since drained from my memory.

[woodsmith]

Its funded almost 6 x already so plenty of people seem to have faith in it being a success.

[jameso]

Its funded almost 6 x already so plenty of people seem to have faith in it being a success.

That's great, good for them. Good to see support for anyone making interesting things in the UK, and we need it.

[woodsmith]

Its funded almost 6 x already so plenty of people seem to have faith in it being a success.

That's great, good for them. Good to see support for anyone making interesting things in the UK, and we need it.

Unfortunately its made in China...

[firestarter]

Looks good it would be good if you could get enough fitting angle on the rack to use it with jones bars , shame I missed the early bird as it looks worth a shot but ive still got a spesh pizza rack ive to bodge fit on my bike

[jameso]

Its funded almost 6 x already so plenty of people seem to have faith in it being a success.

That's great, good for them. Good to see support for anyone making interesting things in the UK, and we need it.

Unfortunately its made in China...

Oh : /
UK brand, thought it was UK made as it was a fairly simple construction.

[redefined_cycles]

I like it heaps. Time will tell if it's robust enough but a weight limit of 5kg, which is far more than even I carry on my bars, sounds like it's built for endurance.

But, James, have you invented a new thing? Roadpacking? What have I missed?

It's for my roadpacker

That's right. James is indeed a roadpacker. Doesn't belong here. Needs to open up his own channel... BillyGoatsRoadpacking.com

[JohnClimber]

Good review. I'd wondered about carrying a packraft on it.

Was thinking this but I've never had a problem with my Wildcat harness for that job and it's a fraction of the weight. I couldn't justify the extra expense when I don't have a problem with what I already use