Jeffsy Primus 24
A 24″ aluminum frame mountain youth bike with upper mid-range components and hydraulic disc brakes.
Compare the full range
For This Bike
4'5" – 5'0"
None yet.
Do you have this bike? Help other riders make a decision about which size will work for them by sharing your own size and fit notes.
Apr 2023
The YT Jeffsy Primus 27 steps up an affordable 150mm all-mountain bike for riders 135cm to 165cm tall (or 4’5” – 5’5”); priced at $2,399
Nov 2022 · Danny Milner
Those who think the youth of today have it too easy look away now, because this Jeffsy Primus is a kids’ bike at least as cool – if not cooler – than anything you could be buying yourself. And if your youngsters look like they could get serious about their riding this will give them an incredible leg-up, opening up burly terrain and big hits for even the youngest of shredder. Be careful what you unleash…this is one of the best kids mountain bikes out there. Need to know Available in 24-inch and 26-inch wheel versions, though not switchable from one to the other Attention to detail extends to narrow grips, custom shock tunes, tubeless prep and more besides Proper tyres open up serious terrain for proper little riders Super active suspension that actually works, even for smaller kids Virtual Four Link design carried straight over from adult sized Jeffsy range No corners cut on the spec, top quality finishing kit from front to back If you started out mountain biking on a rusty Falcon Sierra or wobbly old Raleigh Activator prepare for a shock at how far kids’ bikes have come. And how quickly a quality bike like this awesome looking YT Jeffsy Primo can unleash the proper ripper in your nipper. At a price. Like anything you get what you pay for, and at first glance you know there have been no corners cut shrinking down YT’s popular all-rounder for a younger generation of riders. And the deeper you dig into the spec the more impressive it becomes, the attention to detail underlining a zero-compromise approach that makes the price actually look relatively reasonable – particularly now it’s been reduced by over £400! It starts with the foundations of a sleek looking and well-finished hydroformed aluminium frame based around YT’s Virtual Four Link design, driving a Manitou McLeod shock with 130mm of rear-wheel travel and a four-stage compression switch to configure it to the terrain you’re riding. This is paired with a burly looking, 130mm travel Manitou Machete JUNIT front end whose Expert Air springing promises a kid-optimised response that’s often lacking in the basic forks found on most 24-inch bikes. Quality SunRinglé Düroc wheels are another welcome sight and save a chunk of valuable rotating and unsprung weight compared with the hefty hoops standard on the Marin 24in Rift Zone Jr we had on test at the same time. True, the Minion DHF/DHR tyre combo is probably overkill for all but bike park riding, but points to YT’s intentions, the fact they turned up already tubeless and with Peaty’s valves another satisfying detail. The relatively small 42t top cog on the SRAM 11-speed cassette is another indicator of the Jeffsy Primo’s gravity focused ambitions, even if the stumpy 155mm SRAM SX cranks will help little legs and are acut above the kind of no-name components often found on kids’ bikes. Quality finishing kit from SDG completes the spec, the dinky saddle, 650mm bars and super skinny grips …Continue reading »
Looks fantastic. Kid-optimised attention to detail. Suspension actually works. They’ll love shredding the downhills…
…but the climbs will be a drag on those fat Minions. Not cheap. Limited gearing range. Might not last a growing kid very long.
Aug 2022
The YT Jeffsy 29 Core 3 is a very capable all-mountain bike which can handle the rough stuff but is equally at home on flow trails and jumps. While the specification list is solid for the money, it's worth paying extra attention to frame sizing and geometry to get the ride you want. With a longer dropper and some tougher tyres this bike has what it takes to be a real challenger when it comes to the best mountain bikes.
Aug 2022 · Richard Owen
Like Robocop or the Six Million Dollar Man, YT have rebuilt the Jeffsy with top notch tech to be (even) better than it was before
Superbly capable
Wants to blast every trail
Packed with top tech
Instant freehub engagement
App driven suspension setup
A hefty investment
Slightly conservative geometry
May 2022 · Ed Thomsett
An excellent complete package that makes fun of all but the gnarliest descents, thanks to a head angle that feels too steep
Predictable ride quality
A solid suite of parts
Great for riding just about any terrain
Conservative head angle
A good price, but the outrageous value YT’s reputation was built on isn’t there
Apr 2022 · Matt Beer
Following the recent release of YT's Capra and Decoy MX Uncaged 9 builds is the trail-friendly 150mm Jeffsy Uncaged 8.
Dec 2021 · Lydia Tanner
A great value with an appetite for rowdier trails. .
Incredibly capable
Incredibly fun
Incredibly versatile
Incredible value
Pedal bob had us using the lockout on long climbs
Slightly limited water bottle space
Could use stronger brakes
Oct 2021 · Robert Johnston
The YT Jeffsy 29 Core 4 is a versatile all mountain bike that’ll happily crunch out mellower miles or tackle some tough enduro tracks.
Well-Rounded nature
Capable suspension package
Technical climbing prowess
Steeper head angle in steep terrain
Flimsy tires
Fork | MANITOU MACHETE JUNIT, 24“ | 130 mm | 15mm QR x110mmI 42mm Rake Travel: 130mm |
---|---|
Shock | MANITOU McLeod, 190 x40 mm | 4pos-Adjust I Rebound | Custom Tune Travel: 130mm |
Headset | ACROS AZX-576, High Cap | 2 Spacer 5 mm |
Stem | SDG Jr, 40mm | 31,8 mm I +/-3°Rise |
Handlebar | SDG Slater, 650 mm | 31,8 mm | 20 mm Rise I 8° Back | 5° Up |
Saddle | SDG Fly Jr, YT Custom Design | Width 122 mm |
Seatpost | SDG Jr, Ø 31.6mm | 250 mm I 8 mm Offset I +/-13mm Rise Type: Rigid |
Grips | ODI ELITE MOTION V2.1 , Lock On |
Rear Derailleur | SRAM NX, 11-speed |
---|---|
Crank | SRAM SX X1, 155mm | 30T I DUB |
Shifters | SRAM NX, 11-speed |
Cassette | SRAM PG1130, 11-42 | 11-speed |
Brakes | SRAM Guide R Custom, Rotor CENTERLINE 160mm/160mm Type: Hydraulic Disc |
Rims | SUNRINGLÉ DUROC, 24‘‘ x 30mm I 110 x 15 mm I 148 x 12 mmI HG |
---|---|
Tires | FRONT: MAXXIS MINION DHF I REAR: MAXXIS MINION DHR II, 24’’ x2.4 I3C MaxxTerra I EXO I 24’’x 2.3| DUAL Compound I EXO | TR |
Last updated April 22
Not listed for 356 days