Focus Jam2 factory fork offset and air spring?

[DAZ1925]

Can anybody tell me the fork offset of a standard Jam2 Factory 2017/18, I believe it's a Yari 150mm fork. I've searched high and low on the internet and this forum to no avail. I know these details are usually listed on the back of the fork.

I have recently purchased a Jam2 LTD with a 140mm travel fork and i'm looking at upgrading the fork to either a Pike, Yari or a Lyrik in 150mm

Darren

 

[steve_sordy]

I briefly had a 2018 Jam2 Factory in my possession. It had a Fox 36 Performance fork that had the ID code DBNL. This turned out to be a standard 150mm travel fork that had been altered to suit the 140 travel that the 2018 Jam2 was specified for. The Fox web page said that the "rake" (which I assume is American for offset), was 51mm.

I am further assuming that all 140mm travel forks fitted to the Focus Jam2 will have the same fork offset. Are you convinced yet?

 

[highpeakrider]

I’m not sure if the offset will make much difference?
I just put a 140mm Yari on mine and didn’t even consider it.

Rockshox Yari RC Solo Air Boost OEM - 27.5" | Merlin Cycles

Not a great pic but you can see how it looks

 

[steve_sordy]

I’m not sure if the offset will make much difference?
I just put a 140mm Yari on mine and didn’t even consider it.

Rockshox Yari RC Solo Air Boost OEM - 27.5" | Merlin Cycles

I suspect that you were lucky. Everything I have read so far suggests that fork offset can make a massive difference to the ride of a bike. It is what improved the cornering ability of 29ers after they first came out and were criticised for their barge like steering. Not an expert though, happy to concede to anyone that knows for sure. MTB is full of stuff where small changes can make a massive difference (stem length, bar height, bar width, clicks on your suspension...)

 

[DAZ1925]

Cheers guys, all of the information I have found on Focus's website shows them at 51mm offset but at the same time the geometry measurements suggest that the rear triangle was different as the chainstay is longer on the factory.

Plus LTD
JAM² Plus LTD

Factory
JAM² FACTORY

 

[highpeakrider]

The fork offset of my Jam is 51mm.
JAM² Plus LTD

The fork offset of my Yari is 51mm
https://www.sram.com/sites/default/...ir_coil_token_specification_english_rev_a.pdf

If I put my serial number into the tuning site it’s confirmed as 51

RockShox Setup Guide | SRAM

Offset explanation
Fork offset: what is it and how does it affect your riding? - MBR

I’m sure @Gary will know of talk to TF Tuned or another fork expert.

 

[Gary]

I’m sure @Gary will know

I'd have to know the question first.
From what everyone is saying here the bike is spec'd with a 51mm offset fork. That's pretty much the norm for a 29" fork

Fork offset has become a trendy buzzword in the mtb media and marketing lately. Playing around with offset is nothing new. As in the link above all it does is alter trail. which in turn alters steering and stability (slightly)
If you know what you want to change about your steering characteristics go ahead and buy an alternative offset fork. if not and you're happy with your bike's handling stick with what was spec'd. Whichever way you go the bike will feel normal to you after a few hours of riding anyway.

 

[DAZ1925]

So, the reason I initially asked about the offset was due to the fact all of the websites I'd seen with the Factory specs didn't mention any offset figures and Rockshox stated that they make two offset options, 42 or 51 for the Lyrik and Yari.

I didn't want to alter the geometry but just wanted the increased travel up front offered by a 150mm fork, I know it's not much in the overall scheme of things. So after finding the the geometry on the Focus website maybe what I should be trying to confirm is, if there is a different rear triangle on the two specs as indicated by the difference in the chainstay lengths (457 on the Plus LTD and 470 on the Factory). I've just measured mine and it was 461mm measured between the axle and BB centers.

So if anyone with a factory spec Jam2 could measure there chainstay and let me know that would be great cheers

 

[steve_sordy]

@DAZ1925: When you get the fork make sure that it actually has 150 travel.

I had a very close look at a 2018 Focus Jam2 Factory with a Fox 36 fork. It looked like a 150 travel, the stanchions measured at 150, the tech guy said it was 150 and the sales guy said it was 150. I looked up the ID code and the Fox website said it was 150. Trouble is the 2018 Jam2 are designed for 140mm forks. So when they fitted a Fox 36, they had them altered so that they only delivered 140mm. How do I know? Because I let all the air out and pushed it hard down onto the bump stops. There was 10mm left unused on the stanchion and the travel measured at 140mm.

Why would Focus alter the fork like that? It would have cost some money to alter the fork when they could have had 10mm extra travel for free. Unless it would have upset the geometry of the bike by more than they were comfortable with? I'm assuming the 2019 bikes have been altered in some way to accept the 150mm travel they are now offering as standard.

 

[DAZ1925]

Weird, Seems like the bike industry feels it's ok to blatantly lie to it's customers. Everything I've found on the Jam2 Factory spec states 150mm fork travel with 150mm travel. The Geometry figures seem to be taken with an elastic ruler too and the latest models don't even have any measurements.

I wonder if the Yari fork spec'd on some Factory spec bikes was also reduced.

 

[steve_sordy]

Weird, Seems like the bike industry feels it's ok to blatantly lie to it's customers. Everything I've found on the Jam2 Factory spec states 150mm fork travel with 150mm travel. The Geometry figures seem to be taken with an elastic ruler too and the latest models don't even have any measurements.

I wonder if the Yari fork spec'd on some Factory spec bikes was also reduced.

I very much doubt that blatant lies are being told, or even subtle ones for that matter.

This is what I believe: The 2018 spec is 140mm fork travel. The 2019 is 150mm travel. Rear travel remains the same at 140mm.

I have tried many times to get the geometry for the 2019 bikes; the Focus website shows the geometry table but without any numbers.

 

[DAZ1925]

I very much doubt that blatant lies are being told, or even subtle ones for that matter.

This is what I believe: The 2018 spec is 140mm fork travel. The 2019 is 150mm travel. Rear travel remains the same at 140mm.

I have tried many times to get the geometry for the 2019 bikes; the Focus website shows the geometry table but without any numbers.

The Review below from November 2017 clearly states 150mm travel on a Yari fork.

Focus JAM2 Factory review

In the archive on the Focus website it states 150mm Fox fork as you said there are no geometry measurements for the 2019 models and it looks like they've dropped the factory name in the new line up.

 

[steve_sordy]

I have read that article and I would be happy to accept that Focus did the same with the Yari as they did with the Fox 36, ie tinkered with the travel. I'm not kidding, everyone in the shop thought the Fox 36 fork was a 150, even the Fox ID said it was. I reckon it's a cock up rather than a conspiracy.

Still puzzled though if its in the Focus website. Let's hope that the promises of a 150mm travel fork for the 2019 bikes hold true.

 

[DAZ1925]

I have read that article and I would be happy to accept that Focus did the same with the Yari as they did with the Fox 36, ie tinkered with the travel. I'm not kidding, everyone in the shop thought the Fox 36 fork was a 150, even the Fox ID said it was. I reckon it's a cock up rather than a conspiracy.

Still puzzled though if its in the Focus website. Let's hope that the promises of a 150mm travel fork for the 2019 bikes hold true.

There's plenty of other sources that state the Yari and the Fox 36 equipped bikes are 150mm travel up front and 140mm the rear. It's true that you can reduce the travel but then its no longer a 150mm fork and shouldn't be stated as one. I have read that they tweaked the fork but I'd have thought that was more a dampening tweak than reducing the travel.

Put it this way if you purchased a sports car and the salesman said "it gets really good fuel economy and the emissions a very low" then you ask him how they managed it and his reply is " "Well we put a smaller engine in" You'd walk away or at least should do.

 

[steve_sordy]

There's plenty of other sources that state the Yari and the Fox 36 equipped bikes are 150mm travel up front and 140mm the rear. It's true that you can reduce the travel but then its no longer a 150mm fork and shouldn't be stated as one. I have read that they tweaked the fork but I'd have thought that was more a dampening tweak than reducing the travel.

Put it this way if you purchased a sports car and the salesman said "it gets really good fuel economy and the emissions a very low" then you ask him how they managed it and his reply is " "Well we put a smaller engine in" You'd walk away or at least should do.

I agree! It is what I did when I bought a 2018 version last Thursday. It is went back once I discovered the overstated travel. I just don't believe it was a conspiracy, just a cock up. The mechanic, the sales guy, me, the Fox website all thought the fork was 150. It wasn't.

 

[highpeakrider]

Would you actually notice 10mm you could loose that in sag.
I’ve got a 140 Yari on mine and it feels really balanced.

 

[DAZ1925]

Would you actually notice 10mm you could loose that in sag.
I’ve got a 140 Yari on mine and it feels really balanced.

I know what you mean 10mm extra travel only really equates to 8mm if running 20% sag, It was just the case that if I'm upgrading the fork why not go for the extra travel at the same time as there's no extra cost. I also have a 150mm travel, full sus manual bike so it''s possibly more psychological than anything else. I have seen a post where someone fitted a 160mm fork, not sure I'd want to go that far from standard spec though.

 

[steve_sordy]

Would you actually notice 10mm you could loose that in sag.
I’ve got a 140 Yari on mine and it feels really balanced.

Yes, I know. At the time I thought I was being a bit picky, even for me. But I had made a point of wanting a 150 travel fork and I was more than a bit narked not to get it. I felt no sadness when it went back, so maybe it wasn't the bike for me after all. I still have no regrets. As someone else on here said If you had specified and paid for something and didn't get it, what would you do?

 

[R120]

Don't Fox's have a taller chassis like for like with a RS? Maybe it was to keep the stock geometry

 

[steve_sordy]

Don't Fox's have a taller chassis like for like with a RS? Maybe it was to keep the stock geometry

That is the sort of thing I had assumed would be the reason.

 

[SEBA]

Anyone upgraded to fox 36 stepcast 170mm ?