The new Rondo RATT CF is intended to be a variable-geometry all-road bike with 650b wheels for “going anywhere fast”.
Rondo’s flip chip in the fork can transform the RATT from road bike to gravel bike in minutes, according to the brand.
The RATT incorporates the Polish company’s patented TwinTip technology seen on the Rondo HVRT CF0 road bike and Rondo Ruut AL Disc gravel bike.
The new bike appears to share characteristics of each. Rondo claims the RATT has “the speed of a classic road bike with the all-road character of a modern gravel bike”.
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Like the HVRT CF0, both models of the RATT – the CF1 and CF2 – are claimed to have a 1,000g carbon frame and carbon Rondo TwinTip fork.
Rondo is yet to confirm the bikes’ complete weight, but promises they compete with the fastest on- and off-road.
The top-of-the-range RATT CF1 has a Shimano GRX RX800 groupset, Rondo X Hunt 650B wheels and Vittoria Terreno Zero 47mm tyres.
The CF2 is downgraded to a Shimano GRX RX400 groupset, Rondo LIT wheels and an aluminium instead of carbon seatpost.
The Rondo RATT CF1 costs £4,299 / €4,499 and the Rondo RATT CF2 £3,399 / €3,599.
Adjustable geometry
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The RATT can be switched from the off-road Lo axle position, with more trail, to the on-road Hi axle setting, which reduces trail mid-ride using the TwinTip fork.
To do so, you loosen the front wheel’s thru-axle with a hex key and remove it. Then pull out the wheel and use a T25 Torx to flip the TwinTip. An adaptor amends the angle of the brake rotor.
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In the Hi axle position, the head angle is steeper and the bike’s handling quicker. Rondo says this gives the RATT “race-like agility” while retaining comfort from wider tyres.
This setting replicates a “classic road bike position” for accelerating up steep climbs and when sprinting, according to the brand.
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Switching to the Lo position decreases the offset, making the trail longer and the head tube angle flatter. Rondo claims this setting adds compliance for going over uneven and off-road terrain.
The Rondo RATT CF has “passive suspension zones” at the dropout, lower part of the seat tube and the rear part of the top tube for added comfort, while the rest of the frame remains stiff, according to the brand.
| | Lo | Hi | ||||||
|---|---|---|---|---|---|---|---|---|
| Size (cm) | 51 | 54 | 56 | 58 | 51 | 54 | 56 | 58 |
| Reach (mm) | 370 | 381 | 389 | 395 | 377 | 388 | 397 | 403 |
| Front centre (mm) | 574 | 593 | 608 | 620 | 582 | 600 | 616 | 627 |
| Stack (mm) | 529 | 552 | 576 | 596 | 523 | 547 | 571 | 590 |
| Effective TT (mm) | 531 | 550 | 565 | 577 | 529 | 547 | 563 | 574 |
| Head tube (mm) | 125 | 150 | 175 | 195 | 125 | 150 | 175 | 195 |
| Seat tube (mm) | 490 | 520 | 540 | 570 | 490 | 520 | 540 | 570 |
| Chainstays (mm) | 415 | 415 | 415 | 420 | 415 | 415 | 415 | 420 |
| BB drop (mm) | 65 | 65 | 65 | 65 | 71 | 71 | 71 | 71 |
| Wheelbase (mm) | 980 | 999 | 1,014 | 1,031 | 986 | 1,050 | 1,021 | 1,037 |
| Head tube angle(degrees) | 72.3 | 72.3 | 72.3 | 72.3 | 73.1 | 73.1 | 73.1 | 73.1 |
| Seat tube angle (degrees) | 73 | 73 | 73 | 73 | 73.8 | 73.8 | 73.8 | 73.8 |
| Fork length (mm) | 380 | 380 | 380 | 380 | 370 | 370 | 370 | 370 |
| Fork offset (mm) | 50 | 50 | 50 | 50 | 60 | 60 | 60 | 60 |
| Trail (mm) | 57 | 57 | 57 | 57 | 41 | 41 | 41 | 41 |
Huge tyre clearance
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The Rondo RATT CF is optimised for 650b wheels for “comfort and performance”. The option to fit 700c wheels is aimed at “classic road ride and performance”.
As a result, Rondo specs the RATT with 650b wheels and 47mm Vittoria Terreno Zero tyres, the maximum width the frame accommodates in that wheel diameter.
Rondo explains it opted for 650b wheels on the RATT because smaller wheels can take wide tyres, while minimising overall wheel diameter.
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The company says wider tyres are faster and more comfortable, adding that their larger contact area provides “exceptional traction and stability with reduced rolling resistance without any detrimental effect on the speed.”
The RATT CF has clearance for 700c tyres up to 38mm measured width. Rondo says a road rider could go down as narrow as 28mm.
Gearing
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Although the RATT CF can be run with a 1x setup, Rondo says a double crankset is best for a bike that needs to “go fast and go everywhere”.
The RATT CF1 has the Shimano GRX FC-RX810-2 crankset, with 48/31t chainrings, paired with an 11-speed SunRace CSRX1 Eau 11-32t cassette.
The RATT CF2 uses a Shimano GRX FC-RX600 crankset, with 46/30t chainrings and a 10-speed SunRace CSR0 Tau 11-32t cassette out back.